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href="/blog/leetcode/sort-diagonally">Sort the matrix diagonally</a></li><li class="sidebarItem__DBe"><a class="sidebarItemLink_mo7H" href="/blog/aoc-2022/2nd-week">2nd week of Advent of Code '22 in Rust</a></li></ul></nav></aside><main class="col col--7" itemscope="" itemtype="http://schema.org/Blog"><article itemprop="blogPost" itemscope="" itemtype="http://schema.org/BlogPosting"><header><h1 class="title_f1Hy" itemprop="headline">1st week of Advent of Code '22 in Rust</h1><div class="container_mt6G margin-vert--md"><time datetime="2022-12-15T01:15:00.000Z" itemprop="datePublished">December 15, 2022</time> · <!-- -->13 min read</div><div class="margin-top--md margin-bottom--sm row"><div class="col col--6 authorCol_Hf19"><div class="avatar margin-bottom--sm"><a href="https://gitlab.com/mfocko" target="_blank" rel="noopener noreferrer" class="avatar__photo-link"><img class="avatar__photo" src="https://github.com/mfocko.png" alt="Matej Focko"></a><div class="avatar__intro" itemprop="author" itemscope="" itemtype="https://schema.org/Person"><div class="avatar__name"><a href="https://gitlab.com/mfocko" target="_blank" rel="noopener noreferrer" itemprop="url"><span itemprop="name">Matej Focko</span></a></div><small class="avatar__subtitle" itemprop="description">a.k.a. @mf</small></div></div></div></div></header><div id="__blog-post-container" class="markdown" itemprop="articleBody"><p>Let's go through the first week of <a href="https://adventofcode.com" target="_blank" rel="noopener noreferrer"><em>Advent of Code</em></a> in Rust.</p><div class="theme-admonition theme-admonition-note alert alert--secondary admonition_LlT9"><div class="admonitionHeading_tbUL"><span class="admonitionIcon_kALy"><svg viewBox="0 0 14 16"><path fill-rule="evenodd" d="M6.3 5.69a.942.942 0 0 1-.28-.7c0-.28.09-.52.28-.7.19-.18.42-.28.7-.28.28 0 .52.09.7.28.18.19.28.42.28.7 0 .28-.09.52-.28.7a1 1 0 0 1-.7.3c-.28 0-.52-.11-.7-.3zM8 7.99c-.02-.25-.11-.48-.31-.69-.2-.19-.42-.3-.69-.31H6c-.27.02-.48.13-.69.31-.2.2-.3.44-.31.69h1v3c.02.27.11.5.31.69.2.2.42.31.69.31h1c.27 0 .48-.11.69-.31.2-.19.3-.42.31-.69H8V7.98v.01zM7 2.3c-3.14 0-5.7 2.54-5.7 5.68 0 3.14 2.56 5.7 5.7 5.7s5.7-2.55 5.7-5.7c0-3.15-2.56-5.69-5.7-5.69v.01zM7 .98c3.86 0 7 3.14 7 7s-3.14 7-7 7-7-3.12-7-7 3.14-7 7-7z"></path></svg></span>note</div><div class="admonitionContent_S0QG"><p>If you wish to have a look at the solutions, you can follow them on my <a href="https://gitlab.com/mfocko/advent-of-code-2022" target="_blank" rel="noopener noreferrer">GitLab</a>.
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More specifically in the <a href="https://gitlab.com/mfocko/advent-of-code-2022/-/tree/main/src/bin" target="_blank" rel="noopener noreferrer"><code>/src/bin/</code></a>.</p></div></div><p>I will try to summarize my experience with using Rust for the AoC. Trying it out
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ages ago, I believe it will be <em>pain and suffering</em>, but we will see. For each
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day I will also try to give a tl;dr of the problem, so that you can better imagine
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the relation to my woes or 👍 moments.</p><h2 class="anchor anchorWithStickyNavbar_LWe7" id="day-1-calorie-counting"><a href="https://adventofcode.com/2022/day/1" target="_blank" rel="noopener noreferrer">Day 1: Calorie Counting</a><a href="#day-1-calorie-counting" class="hash-link" aria-label="Direct link to day-1-calorie-counting" title="Direct link to day-1-calorie-counting"></a></h2><div class="theme-admonition theme-admonition-info alert alert--info admonition_LlT9"><div class="admonitionHeading_tbUL"><span class="admonitionIcon_kALy"><svg viewBox="0 0 14 16"><path fill-rule="evenodd" d="M7 2.3c3.14 0 5.7 2.56 5.7 5.7s-2.56 5.7-5.7 5.7A5.71 5.71 0 0 1 1.3 8c0-3.14 2.56-5.7 5.7-5.7zM7 1C3.14 1 0 4.14 0 8s3.14 7 7 7 7-3.14 7-7-3.14-7-7-7zm1 3H6v5h2V4zm0 6H6v2h2v-2z"></path></svg></span>tl;dr</div><div class="admonitionContent_S0QG"><p>As the name suggests, we get the calories of the food contained in the elves
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backpacks and we want to choose the elf that has the most food ;)</p></div></div><blockquote><p>Wakey wakey!</p></blockquote><p>Programming in Rust at 6am definitely hits. I've also forgotten to mention how I
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handle samples. With each puzzle you usually get a sample input and expected
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output. You can use them to verify that your solution works, or usually doesn't.</p><p>At first I've decided to put asserts into my <code>main</code>, something like</p><div class="language-rust codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#ffffff"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-rust codeBlock_bY9V thin-scrollbar"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token macro property">assert_eq!</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token function" style="color:rgb(0, 0, 255)">part_1</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token operator" style="color:rgb(0, 0, 0)">&</span><span class="token plain">sample</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">24000</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token macro property">info!</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token string" style="color:rgb(163, 21, 21)">"Part 1: {}"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token function" style="color:rgb(0, 0, 255)">part_1</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token operator" style="color:rgb(0, 0, 0)">&</span><span class="token plain">input</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token macro property">assert_eq!</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token function" style="color:rgb(0, 0, 255)">part_2</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token operator" style="color:rgb(0, 0, 0)">&</span><span class="token plain">sample</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">45000</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token macro property">info!</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token string" style="color:rgb(163, 21, 21)">"Part 2: {}"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token function" style="color:rgb(0, 0, 255)">part_2</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token operator" style="color:rgb(0, 0, 0)">&</span><span class="token plain">input</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">;</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div><p>However, once you get further, the sample input may take some time to run itself.
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So in the end, I have decided to turn them into unit tests:</p><div class="language-rust codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#ffffff"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-rust codeBlock_bY9V thin-scrollbar"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token attribute attr-name" style="color:rgb(255, 0, 0)">#[cfg(test)]</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token keyword" style="color:rgb(0, 0, 255)">mod</span><span class="token plain"> </span><span class="token module-declaration namespace">tests</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">{</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> </span><span class="token keyword" style="color:rgb(0, 0, 255)">use</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(0, 0, 255)">super</span><span class="token punctuation" style="color:rgb(4, 81, 165)">::</span><span class="token operator" style="color:rgb(0, 0, 0)">*</span><span class="token punctuation" style="color:rgb(4, 81, 165)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> </span><span class="token attribute attr-name" style="color:rgb(255, 0, 0)">#[test]</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> </span><span class="token keyword" style="color:rgb(0, 0, 255)">fn</span><span class="token plain"> </span><span class="token function-definition function" style="color:rgb(0, 0, 255)">test_part_1</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">{</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> </span><span class="token keyword" style="color:rgb(0, 0, 255)">let</span><span class="token plain"> sample </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token function" style="color:rgb(0, 0, 255)">parse_input</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token string" style="color:rgb(163, 21, 21)">"samples/day01.txt"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> </span><span class="token macro property">assert_eq!</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token function" style="color:rgb(0, 0, 255)">part_1</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token operator" style="color:rgb(0, 0, 0)">&</span><span class="token plain">sample</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">24000</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">}</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> </span><span class="token attribute attr-name" style="color:rgb(255, 0, 0)">#[test]</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> </span><span class="token keyword" style="color:rgb(0, 0, 255)">fn</span><span class="token plain"> </span><span class="token function-definition function" style="color:rgb(0, 0, 255)">test_part_2</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">{</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> </span><span class="token keyword" style="color:rgb(0, 0, 255)">let</span><span class="token plain"> sample </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token function" style="color:rgb(0, 0, 255)">parse_input</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token string" style="color:rgb(163, 21, 21)">"samples/day01.txt"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> </span><span class="token macro property">assert_eq!</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token function" style="color:rgb(0, 0, 255)">part_2</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token operator" style="color:rgb(0, 0, 0)">&</span><span class="token plain">sample</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">45000</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">}</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token punctuation" style="color:rgb(4, 81, 165)">}</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div><p>And later on I have noticed, it's hard to tell the difference between the days,
|
||
so I further renamed the <code>mod</code> from generic <code>tests</code> to reflect the days.</p><p>Also after finishing the first day puzzle, I have installed an <a href="https://github.com/mozilla/sccache" target="_blank" rel="noopener noreferrer"><code>sccache</code></a> to
|
||
cache the builds, so that the build time is lower, cause it was kinda unbearable.</p><h3 class="anchor anchorWithStickyNavbar_LWe7" id="solution">Solution<a href="#solution" class="hash-link" aria-label="Direct link to Solution" title="Direct link to Solution"></a></h3><p>Well, it's a pretty simple problem. You just take the input, sum the calories and
|
||
find the biggest one. However, if we try to generalize to more than the biggest
|
||
one, the fun appears. We have few options:</p><ul><li>keep all the calories, sort them, take what we need</li><li>keep all the calories and use max heap</li><li>use min heap and maintain at most N calories that we need</li></ul><h2 class="anchor anchorWithStickyNavbar_LWe7" id="day-2-rock-paper-scissors"><a href="https://adventofcode.com/2022/day/2" target="_blank" rel="noopener noreferrer">Day 2: Rock Paper Scissors</a><a href="#day-2-rock-paper-scissors" class="hash-link" aria-label="Direct link to day-2-rock-paper-scissors" title="Direct link to day-2-rock-paper-scissors"></a></h2><div class="theme-admonition theme-admonition-info alert alert--info admonition_LlT9"><div class="admonitionHeading_tbUL"><span class="admonitionIcon_kALy"><svg viewBox="0 0 14 16"><path fill-rule="evenodd" d="M7 2.3c3.14 0 5.7 2.56 5.7 5.7s-2.56 5.7-5.7 5.7A5.71 5.71 0 0 1 1.3 8c0-3.14 2.56-5.7 5.7-5.7zM7 1C3.14 1 0 4.14 0 8s3.14 7 7 7 7-3.14 7-7-3.14-7-7-7zm1 3H6v5h2V4zm0 6H6v2h2v-2z"></path></svg></span>tl;dr</div><div class="admonitionContent_S0QG"><p>You want to know what score did you achieve while playing <em>Rock Paper Scissors</em>.
|
||
And then you want to be strategic about it.</p></div></div><p>Apart from the technical details of the puzzle, it went relatively smooth.</p><h3 class="anchor anchorWithStickyNavbar_LWe7" id="solution-1">Solution<a href="#solution-1" class="hash-link" aria-label="Direct link to Solution" title="Direct link to Solution"></a></h3><p>I took relatively naïve approach and then tried to simplify it.</p><h2 class="anchor anchorWithStickyNavbar_LWe7" id="day-3-rucksack-reorganization"><a href="https://adventofcode.com/2022/day/3" target="_blank" rel="noopener noreferrer">Day 3: Rucksack Reorganization</a><a href="#day-3-rucksack-reorganization" class="hash-link" aria-label="Direct link to day-3-rucksack-reorganization" title="Direct link to day-3-rucksack-reorganization"></a></h2><div class="theme-admonition theme-admonition-info alert alert--info admonition_LlT9"><div class="admonitionHeading_tbUL"><span class="admonitionIcon_kALy"><svg viewBox="0 0 14 16"><path fill-rule="evenodd" d="M7 2.3c3.14 0 5.7 2.56 5.7 5.7s-2.56 5.7-5.7 5.7A5.71 5.71 0 0 1 1.3 8c0-3.14 2.56-5.7 5.7-5.7zM7 1C3.14 1 0 4.14 0 8s3.14 7 7 7 7-3.14 7-7-3.14-7-7-7zm1 3H6v5h2V4zm0 6H6v2h2v-2z"></path></svg></span>tl;dr</div><div class="admonitionContent_S0QG"><p>Let's go reorganize elves' backpacks! Each backpacks has 2 compartments and you
|
||
want to find the common item among those compartments. Each of them has priority,
|
||
you care only about the sum.</p></div></div><p>This is the day where I started to fight the compiler and neither of us decided
|
||
to give up. Let's dive into it \o/</p><div class="theme-admonition theme-admonition-tip alert alert--success admonition_LlT9"><div class="admonitionHeading_tbUL"><span class="admonitionIcon_kALy"><svg viewBox="0 0 12 16"><path fill-rule="evenodd" d="M6.5 0C3.48 0 1 2.19 1 5c0 .92.55 2.25 1 3 1.34 2.25 1.78 2.78 2 4v1h5v-1c.22-1.22.66-1.75 2-4 .45-.75 1-2.08 1-3 0-2.81-2.48-5-5.5-5zm3.64 7.48c-.25.44-.47.8-.67 1.11-.86 1.41-1.25 2.06-1.45 3.23-.02.05-.02.11-.02.17H5c0-.06 0-.13-.02-.17-.2-1.17-.59-1.83-1.45-3.23-.2-.31-.42-.67-.67-1.11C2.44 6.78 2 5.65 2 5c0-2.2 2.02-4 4.5-4 1.22 0 2.36.42 3.22 1.19C10.55 2.94 11 3.94 11 5c0 .66-.44 1.78-.86 2.48zM4 14h5c-.23 1.14-1.3 2-2.5 2s-2.27-.86-2.5-2z"></path></svg></span>Fun fact</div><div class="admonitionContent_S0QG"><p>Fighting the compiler took me 30 minutes.</p></div></div><p>We need to find a common item among 2 collections, that's an easy task, right?
|
||
We can construct 2 sets and find an intersection:</p><div class="language-rust codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#ffffff"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-rust codeBlock_bY9V thin-scrollbar"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token keyword" style="color:rgb(0, 0, 255)">let</span><span class="token plain"> top</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token class-name" style="color:rgb(38, 127, 153)">HashSet</span><span class="token operator" style="color:rgb(0, 0, 0)"><</span><span class="token keyword" style="color:rgb(0, 0, 255)">i32</span><span class="token operator" style="color:rgb(0, 0, 0)">></span><span class="token plain"> </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token number" style="color:rgb(9, 134, 88)">1</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">2</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">3</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token function" style="color:rgb(0, 0, 255)">iter</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token function" style="color:rgb(0, 0, 255)">collect</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token keyword" style="color:rgb(0, 0, 255)">let</span><span class="token plain"> bottom</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token class-name" style="color:rgb(38, 127, 153)">HashSet</span><span class="token operator" style="color:rgb(0, 0, 0)"><</span><span class="token keyword" style="color:rgb(0, 0, 255)">i32</span><span class="token operator" style="color:rgb(0, 0, 0)">></span><span class="token plain"> </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token number" style="color:rgb(9, 134, 88)">3</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">4</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">5</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token function" style="color:rgb(0, 0, 255)">iter</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token function" style="color:rgb(0, 0, 255)">collect</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">;</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div><p>Now, the first issue that we encounter is caused by the fact that we are using
|
||
a slice (the <code>[…]</code>), iterator of that returns <strong>references</strong> to the numbers.
|
||
And we get immediately yelled at by the compiler, because the numbers are discarded
|
||
after running the <code>.collect</code>. To fix this, we can use <code>.into_iter</code>:</p><div class="language-rust codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#ffffff"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-rust codeBlock_bY9V thin-scrollbar"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token keyword" style="color:rgb(0, 0, 255)">let</span><span class="token plain"> top</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token class-name" style="color:rgb(38, 127, 153)">HashSet</span><span class="token operator" style="color:rgb(0, 0, 0)"><</span><span class="token keyword" style="color:rgb(0, 0, 255)">i32</span><span class="token operator" style="color:rgb(0, 0, 0)">></span><span class="token plain"> </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token number" style="color:rgb(9, 134, 88)">1</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">2</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">3</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token function" style="color:rgb(0, 0, 255)">into_iter</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token function" style="color:rgb(0, 0, 255)">collect</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token keyword" style="color:rgb(0, 0, 255)">let</span><span class="token plain"> bottom</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token class-name" style="color:rgb(38, 127, 153)">HashSet</span><span class="token operator" style="color:rgb(0, 0, 0)"><</span><span class="token keyword" style="color:rgb(0, 0, 255)">i32</span><span class="token operator" style="color:rgb(0, 0, 0)">></span><span class="token plain"> </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token number" style="color:rgb(9, 134, 88)">3</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">4</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">5</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token function" style="color:rgb(0, 0, 255)">into_iter</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token function" style="color:rgb(0, 0, 255)">collect</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">;</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div><p>This way the numbers will get copied instead of referenced. OK, let's find the
|
||
intersection of those 2 collections:</p><div class="language-rust codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#ffffff"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-rust codeBlock_bY9V thin-scrollbar"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token macro property">println!</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token string" style="color:rgb(163, 21, 21)">"Common elements: {:?}"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> top</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token function" style="color:rgb(0, 0, 255)">intersection</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token operator" style="color:rgb(0, 0, 0)">&</span><span class="token plain">bottom</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">;</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div><div class="codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#ffffff"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-text codeBlock_bY9V thin-scrollbar"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token plain">Common elements: [3]</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div><div class="theme-admonition theme-admonition-caution alert alert--warning admonition_LlT9"><div class="admonitionHeading_tbUL"><span class="admonitionIcon_kALy"><svg viewBox="0 0 16 16"><path fill-rule="evenodd" d="M8.893 1.5c-.183-.31-.52-.5-.887-.5s-.703.19-.886.5L.138 13.499a.98.98 0 0 0 0 1.001c.193.31.53.501.886.501h13.964c.367 0 .704-.19.877-.5a1.03 1.03 0 0 0 .01-1.002L8.893 1.5zm.133 11.497H6.987v-2.003h2.039v2.003zm0-3.004H6.987V5.987h2.039v4.006z"></path></svg></span>caution</div><div class="admonitionContent_S0QG"><p>Notice that we need to do <code>&bottom</code>. It explicitly specifies that <code>.intersection</code>
|
||
<strong>borrows</strong> the <code>bottom</code>, i.e. takes an immutable reference to it.</p></div></div><p>That's what we want, right? Looks like it! \o/</p><p>Next part wants us to find the common element among all of the backpacks. OK, so
|
||
that should be fairly easy, we have an intersection and we want to find intersection
|
||
over all of them.</p><p>Let's have a look at the type of the <code>.intersection</code></p><div class="language-rust codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#ffffff"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-rust codeBlock_bY9V thin-scrollbar"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token keyword" style="color:rgb(0, 0, 255)">pub</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(0, 0, 255)">fn</span><span class="token plain"> </span><span class="token function-definition function" style="color:rgb(0, 0, 255)">intersection</span><span class="token operator" style="color:rgb(0, 0, 0)"><</span><span class="token lifetime-annotation symbol">'a</span><span class="token operator" style="color:rgb(0, 0, 0)">></span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> </span><span class="token operator" style="color:rgb(0, 0, 0)">&</span><span class="token lifetime-annotation symbol">'a</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(0, 0, 255)">self</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> other</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token operator" style="color:rgb(0, 0, 0)">&</span><span class="token lifetime-annotation symbol">'a</span><span class="token plain"> </span><span class="token class-name" style="color:rgb(38, 127, 153)">HashSet</span><span class="token operator" style="color:rgb(0, 0, 0)"><</span><span class="token class-name" style="color:rgb(38, 127, 153)">T</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token class-name" style="color:rgb(38, 127, 153)">S</span><span class="token operator" style="color:rgb(0, 0, 0)">></span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">-></span><span class="token plain"> </span><span class="token class-name" style="color:rgb(38, 127, 153)">Intersection</span><span class="token operator" style="color:rgb(0, 0, 0)"><</span><span class="token lifetime-annotation symbol">'a</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token class-name" style="color:rgb(38, 127, 153)">T</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token class-name" style="color:rgb(38, 127, 153)">S</span><span class="token operator" style="color:rgb(0, 0, 0)">></span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div><p>OK… Huh… But we have an example there!</p><div class="language-rust codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#ffffff"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-rust codeBlock_bY9V thin-scrollbar"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token keyword" style="color:rgb(0, 0, 255)">let</span><span class="token plain"> intersection</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token class-name" style="color:rgb(38, 127, 153)">HashSet</span><span class="token operator" style="color:rgb(0, 0, 0)"><</span><span class="token plain">_</span><span class="token operator" style="color:rgb(0, 0, 0)">></span><span class="token plain"> </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> a</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token function" style="color:rgb(0, 0, 255)">intersection</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token operator" style="color:rgb(0, 0, 0)">&</span><span class="token plain">b</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token function" style="color:rgb(0, 0, 255)">collect</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">;</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div><p>Cool, that's all we need.</p><div class="language-rust codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#ffffff"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-rust codeBlock_bY9V thin-scrollbar"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token keyword" style="color:rgb(0, 0, 255)">let</span><span class="token plain"> top</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token class-name" style="color:rgb(38, 127, 153)">HashSet</span><span class="token operator" style="color:rgb(0, 0, 0)"><</span><span class="token keyword" style="color:rgb(0, 0, 255)">i32</span><span class="token operator" style="color:rgb(0, 0, 0)">></span><span class="token plain"> </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token number" style="color:rgb(9, 134, 88)">1</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">2</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">3</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">4</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token function" style="color:rgb(0, 0, 255)">into_iter</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token function" style="color:rgb(0, 0, 255)">collect</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token keyword" style="color:rgb(0, 0, 255)">let</span><span class="token plain"> bottom</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token class-name" style="color:rgb(38, 127, 153)">HashSet</span><span class="token operator" style="color:rgb(0, 0, 0)"><</span><span class="token keyword" style="color:rgb(0, 0, 255)">i32</span><span class="token operator" style="color:rgb(0, 0, 0)">></span><span class="token plain"> </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token number" style="color:rgb(9, 134, 88)">3</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">4</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">5</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">6</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token function" style="color:rgb(0, 0, 255)">into_iter</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token function" style="color:rgb(0, 0, 255)">collect</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token keyword" style="color:rgb(0, 0, 255)">let</span><span class="token plain"> top_2</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token class-name" style="color:rgb(38, 127, 153)">HashSet</span><span class="token operator" style="color:rgb(0, 0, 0)"><</span><span class="token keyword" style="color:rgb(0, 0, 255)">i32</span><span class="token operator" style="color:rgb(0, 0, 0)">></span><span class="token plain"> </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token number" style="color:rgb(9, 134, 88)">2</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">3</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">4</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">5</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">6</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token function" style="color:rgb(0, 0, 255)">into_iter</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token function" style="color:rgb(0, 0, 255)">collect</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token keyword" style="color:rgb(0, 0, 255)">let</span><span class="token plain"> bottom_2</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token class-name" style="color:rgb(38, 127, 153)">HashSet</span><span class="token operator" style="color:rgb(0, 0, 0)"><</span><span class="token keyword" style="color:rgb(0, 0, 255)">i32</span><span class="token operator" style="color:rgb(0, 0, 0)">></span><span class="token plain"> </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token number" style="color:rgb(9, 134, 88)">4</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">5</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">6</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token function" style="color:rgb(0, 0, 255)">into_iter</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token function" style="color:rgb(0, 0, 255)">collect</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token keyword" style="color:rgb(0, 0, 255)">let</span><span class="token plain"> intersection</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token class-name" style="color:rgb(38, 127, 153)">HashSet</span><span class="token operator" style="color:rgb(0, 0, 0)"><</span><span class="token plain">_</span><span class="token operator" style="color:rgb(0, 0, 0)">></span><span class="token plain"> </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> top</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token function" style="color:rgb(0, 0, 255)">intersection</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token operator" style="color:rgb(0, 0, 0)">&</span><span class="token plain">bottom</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token function" style="color:rgb(0, 0, 255)">collect</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token macro property">println!</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token string" style="color:rgb(163, 21, 21)">"Intersection: {:?}"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> intersection</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">;</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div><div class="codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#ffffff"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-text codeBlock_bY9V thin-scrollbar"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token plain">Intersection: {3, 4}</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div><p>Cool, so let's do the intersection with the <code>top_2</code>:</p><div class="language-rust codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#ffffff"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-rust codeBlock_bY9V thin-scrollbar"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token keyword" style="color:rgb(0, 0, 255)">let</span><span class="token plain"> top</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token class-name" style="color:rgb(38, 127, 153)">HashSet</span><span class="token operator" style="color:rgb(0, 0, 0)"><</span><span class="token keyword" style="color:rgb(0, 0, 255)">i32</span><span class="token operator" style="color:rgb(0, 0, 0)">></span><span class="token plain"> </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token number" style="color:rgb(9, 134, 88)">1</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">2</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">3</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">4</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token function" style="color:rgb(0, 0, 255)">into_iter</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token function" style="color:rgb(0, 0, 255)">collect</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token keyword" style="color:rgb(0, 0, 255)">let</span><span class="token plain"> bottom</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token class-name" style="color:rgb(38, 127, 153)">HashSet</span><span class="token operator" style="color:rgb(0, 0, 0)"><</span><span class="token keyword" style="color:rgb(0, 0, 255)">i32</span><span class="token operator" style="color:rgb(0, 0, 0)">></span><span class="token plain"> </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token number" style="color:rgb(9, 134, 88)">3</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">4</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">5</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">6</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token function" style="color:rgb(0, 0, 255)">into_iter</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token function" style="color:rgb(0, 0, 255)">collect</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token keyword" style="color:rgb(0, 0, 255)">let</span><span class="token plain"> top_2</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token class-name" style="color:rgb(38, 127, 153)">HashSet</span><span class="token operator" style="color:rgb(0, 0, 0)"><</span><span class="token keyword" style="color:rgb(0, 0, 255)">i32</span><span class="token operator" style="color:rgb(0, 0, 0)">></span><span class="token plain"> </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token number" style="color:rgb(9, 134, 88)">2</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">3</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">4</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">5</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">6</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token function" style="color:rgb(0, 0, 255)">into_iter</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token function" style="color:rgb(0, 0, 255)">collect</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token keyword" style="color:rgb(0, 0, 255)">let</span><span class="token plain"> bottom_2</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token class-name" style="color:rgb(38, 127, 153)">HashSet</span><span class="token operator" style="color:rgb(0, 0, 0)"><</span><span class="token keyword" style="color:rgb(0, 0, 255)">i32</span><span class="token operator" style="color:rgb(0, 0, 0)">></span><span class="token plain"> </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token number" style="color:rgb(9, 134, 88)">4</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">5</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">6</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token function" style="color:rgb(0, 0, 255)">into_iter</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token function" style="color:rgb(0, 0, 255)">collect</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token keyword" style="color:rgb(0, 0, 255)">let</span><span class="token plain"> intersection</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token class-name" style="color:rgb(38, 127, 153)">HashSet</span><span class="token operator" style="color:rgb(0, 0, 0)"><</span><span class="token plain">_</span><span class="token operator" style="color:rgb(0, 0, 0)">></span><span class="token plain"> </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> top</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token function" style="color:rgb(0, 0, 255)">intersection</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token operator" style="color:rgb(0, 0, 0)">&</span><span class="token plain">bottom</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token function" style="color:rgb(0, 0, 255)">collect</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token keyword" style="color:rgb(0, 0, 255)">let</span><span class="token plain"> intersection</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token class-name" style="color:rgb(38, 127, 153)">HashSet</span><span class="token operator" style="color:rgb(0, 0, 0)"><</span><span class="token plain">_</span><span class="token operator" style="color:rgb(0, 0, 0)">></span><span class="token plain"> </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> intersection</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token function" style="color:rgb(0, 0, 255)">intersection</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token operator" style="color:rgb(0, 0, 0)">&</span><span class="token plain">top_2</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token function" style="color:rgb(0, 0, 255)">collect</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token macro property">println!</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token string" style="color:rgb(163, 21, 21)">"Intersection: {:?}"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> intersection</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">;</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div><p>And we get yelled at by the compiler:</p><div class="codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#ffffff"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-text codeBlock_bY9V thin-scrollbar"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token plain">error[E0308]: mismatched types</span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> --> src/main.rs:10:58</span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> |</span><br></span><span class="token-line" style="color:#000000"><span class="token plain">10 | let intersection: HashSet<_> = intersection.intersection(&top_2).collect();</span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> | ------------ ^^^^^^ expected `&i32`, found `i32`</span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> | |</span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> | arguments to this function are incorrect</span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> |</span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> = note: expected reference `&HashSet<&i32>`</span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> found reference `&HashSet<i32>`</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div><p>/o\ What the hell is going on here? Well, the funny thing is, that this operation
|
||
doesn't return the elements themselves, but the references to them and when we pass
|
||
the third set, it has just the values themselves, without any references.</p><div class="theme-admonition theme-admonition-tip alert alert--success admonition_LlT9"><div class="admonitionHeading_tbUL"><span class="admonitionIcon_kALy"><svg viewBox="0 0 12 16"><path fill-rule="evenodd" d="M6.5 0C3.48 0 1 2.19 1 5c0 .92.55 2.25 1 3 1.34 2.25 1.78 2.78 2 4v1h5v-1c.22-1.22.66-1.75 2-4 .45-.75 1-2.08 1-3 0-2.81-2.48-5-5.5-5zm3.64 7.48c-.25.44-.47.8-.67 1.11-.86 1.41-1.25 2.06-1.45 3.23-.02.05-.02.11-.02.17H5c0-.06 0-.13-.02-.17-.2-1.17-.59-1.83-1.45-3.23-.2-.31-.42-.67-.67-1.11C2.44 6.78 2 5.65 2 5c0-2.2 2.02-4 4.5-4 1.22 0 2.36.42 3.22 1.19C10.55 2.94 11 3.94 11 5c0 .66-.44 1.78-.86 2.48zM4 14h5c-.23 1.14-1.3 2-2.5 2s-2.27-.86-2.5-2z"></path></svg></span>tip</div><div class="admonitionContent_S0QG"><p>It may seem as a very weird decision, but in fact it makes some sense… It allows
|
||
you to do intersection of items that may not be possible to copy. Overall this is
|
||
a “tax” for having a borrow checker <del>drilling your ass</del> having your back and
|
||
making sure you're not doing something naughty that may cause an <strong>undefined</strong>
|
||
<strong>behavior</strong>.</p></div></div><p>To resolve this we need to get an iterator that <strong>clones</strong> the elements:</p><div class="language-rust codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#ffffff"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-rust codeBlock_bY9V thin-scrollbar"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token keyword" style="color:rgb(0, 0, 255)">let</span><span class="token plain"> top</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token class-name" style="color:rgb(38, 127, 153)">HashSet</span><span class="token operator" style="color:rgb(0, 0, 0)"><</span><span class="token keyword" style="color:rgb(0, 0, 255)">i32</span><span class="token operator" style="color:rgb(0, 0, 0)">></span><span class="token plain"> </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token number" style="color:rgb(9, 134, 88)">1</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">2</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">3</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">4</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token function" style="color:rgb(0, 0, 255)">into_iter</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token function" style="color:rgb(0, 0, 255)">collect</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token keyword" style="color:rgb(0, 0, 255)">let</span><span class="token plain"> bottom</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token class-name" style="color:rgb(38, 127, 153)">HashSet</span><span class="token operator" style="color:rgb(0, 0, 0)"><</span><span class="token keyword" style="color:rgb(0, 0, 255)">i32</span><span class="token operator" style="color:rgb(0, 0, 0)">></span><span class="token plain"> </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token number" style="color:rgb(9, 134, 88)">3</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">4</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">5</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">6</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token function" style="color:rgb(0, 0, 255)">into_iter</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token function" style="color:rgb(0, 0, 255)">collect</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token keyword" style="color:rgb(0, 0, 255)">let</span><span class="token plain"> top_2</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token class-name" style="color:rgb(38, 127, 153)">HashSet</span><span class="token operator" style="color:rgb(0, 0, 0)"><</span><span class="token keyword" style="color:rgb(0, 0, 255)">i32</span><span class="token operator" style="color:rgb(0, 0, 0)">></span><span class="token plain"> </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token number" style="color:rgb(9, 134, 88)">2</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">3</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">4</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">5</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">6</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token function" style="color:rgb(0, 0, 255)">into_iter</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token function" style="color:rgb(0, 0, 255)">collect</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token keyword" style="color:rgb(0, 0, 255)">let</span><span class="token plain"> bottom_2</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token class-name" style="color:rgb(38, 127, 153)">HashSet</span><span class="token operator" style="color:rgb(0, 0, 0)"><</span><span class="token keyword" style="color:rgb(0, 0, 255)">i32</span><span class="token operator" style="color:rgb(0, 0, 0)">></span><span class="token plain"> </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token number" style="color:rgb(9, 134, 88)">4</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">5</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">6</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token function" style="color:rgb(0, 0, 255)">into_iter</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token function" style="color:rgb(0, 0, 255)">collect</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token keyword" style="color:rgb(0, 0, 255)">let</span><span class="token plain"> intersection</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token class-name" style="color:rgb(38, 127, 153)">HashSet</span><span class="token operator" style="color:rgb(0, 0, 0)"><</span><span class="token plain">_</span><span class="token operator" style="color:rgb(0, 0, 0)">></span><span class="token plain"> </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> top</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token function" style="color:rgb(0, 0, 255)">intersection</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token operator" style="color:rgb(0, 0, 0)">&</span><span class="token plain">bottom</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token function" style="color:rgb(0, 0, 255)">cloned</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token function" style="color:rgb(0, 0, 255)">collect</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token keyword" style="color:rgb(0, 0, 255)">let</span><span class="token plain"> intersection</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token class-name" style="color:rgb(38, 127, 153)">HashSet</span><span class="token operator" style="color:rgb(0, 0, 0)"><</span><span class="token plain">_</span><span class="token operator" style="color:rgb(0, 0, 0)">></span><span class="token plain"> </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> intersection</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token function" style="color:rgb(0, 0, 255)">intersection</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token operator" style="color:rgb(0, 0, 0)">&</span><span class="token plain">top_2</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token function" style="color:rgb(0, 0, 255)">cloned</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token function" style="color:rgb(0, 0, 255)">collect</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token keyword" style="color:rgb(0, 0, 255)">let</span><span class="token plain"> intersection</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token class-name" style="color:rgb(38, 127, 153)">HashSet</span><span class="token operator" style="color:rgb(0, 0, 0)"><</span><span class="token plain">_</span><span class="token operator" style="color:rgb(0, 0, 0)">></span><span class="token plain"> </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> intersection</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token function" style="color:rgb(0, 0, 255)">intersection</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token operator" style="color:rgb(0, 0, 0)">&</span><span class="token plain">bottom_2</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token function" style="color:rgb(0, 0, 255)">cloned</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token function" style="color:rgb(0, 0, 255)">collect</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token macro property">println!</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token string" style="color:rgb(163, 21, 21)">"Intersection: {:?}"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> intersection</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">;</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div><div class="codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#ffffff"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-text codeBlock_bY9V thin-scrollbar"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token plain">Intersection: {4}</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div><h3 class="anchor anchorWithStickyNavbar_LWe7" id="solution-2">Solution<a href="#solution-2" class="hash-link" aria-label="Direct link to Solution" title="Direct link to Solution"></a></h3><p>The approach is pretty simple, if you omit the <em>1on1 with the compiler</em>. You just
|
||
have some fun with the set operations :)</p><h2 class="anchor anchorWithStickyNavbar_LWe7" id="day-4-camp-cleanup"><a href="https://adventofcode.com/2022/day/4" target="_blank" rel="noopener noreferrer">Day 4: Camp Cleanup</a><a href="#day-4-camp-cleanup" class="hash-link" aria-label="Direct link to day-4-camp-cleanup" title="Direct link to day-4-camp-cleanup"></a></h2><div class="theme-admonition theme-admonition-info alert alert--info admonition_LlT9"><div class="admonitionHeading_tbUL"><span class="admonitionIcon_kALy"><svg viewBox="0 0 14 16"><path fill-rule="evenodd" d="M7 2.3c3.14 0 5.7 2.56 5.7 5.7s-2.56 5.7-5.7 5.7A5.71 5.71 0 0 1 1.3 8c0-3.14 2.56-5.7 5.7-5.7zM7 1C3.14 1 0 4.14 0 8s3.14 7 7 7 7-3.14 7-7-3.14-7-7-7zm1 3H6v5h2V4zm0 6H6v2h2v-2z"></path></svg></span>tl;dr</div><div class="admonitionContent_S0QG"><p>Elves are cleaning up the camp and they got overlapping sections to clean up.
|
||
Find how many overlap and can take the day off.</p></div></div><p><a href="https://doc.rust-lang.org/std/ops/struct.RangeInclusive.html" target="_blank" rel="noopener noreferrer"><code>RangeInclusive</code></a> is your friend not an enemy :)</p><h3 class="anchor anchorWithStickyNavbar_LWe7" id="solution-3">Solution<a href="#solution-3" class="hash-link" aria-label="Direct link to Solution" title="Direct link to Solution"></a></h3><p>Relatively easy, you just need to parse the input and know what you want. Rust's
|
||
<code>RangeInclusive</code> type helped a lot, cause it took care of all abstractions.</p><h2 class="anchor anchorWithStickyNavbar_LWe7" id="day-5-supply-stacks"><a href="https://adventofcode.com/2022/day/5" target="_blank" rel="noopener noreferrer">Day 5: Supply Stacks</a><a href="#day-5-supply-stacks" class="hash-link" aria-label="Direct link to day-5-supply-stacks" title="Direct link to day-5-supply-stacks"></a></h2><div class="theme-admonition theme-admonition-info alert alert--info admonition_LlT9"><div class="admonitionHeading_tbUL"><span class="admonitionIcon_kALy"><svg viewBox="0 0 14 16"><path fill-rule="evenodd" d="M7 2.3c3.14 0 5.7 2.56 5.7 5.7s-2.56 5.7-5.7 5.7A5.71 5.71 0 0 1 1.3 8c0-3.14 2.56-5.7 5.7-5.7zM7 1C3.14 1 0 4.14 0 8s3.14 7 7 7 7-3.14 7-7-3.14-7-7-7zm1 3H6v5h2V4zm0 6H6v2h2v-2z"></path></svg></span>tl;dr</div><div class="admonitionContent_S0QG"><p>Let's play with stacks of crates.</p></div></div><p>Very easy problem with very annoying input. You can judge yourself:</p><div class="codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#ffffff"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-text codeBlock_bY9V thin-scrollbar"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token plain"> [D] </span><br></span><span class="token-line" style="color:#000000"><span class="token plain">[N] [C] </span><br></span><span class="token-line" style="color:#000000"><span class="token plain">[Z] [M] [P]</span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> 1 2 3 </span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">move 1 from 2 to 1</span><br></span><span class="token-line" style="color:#000000"><span class="token plain">move 3 from 1 to 3</span><br></span><span class="token-line" style="color:#000000"><span class="token plain">move 2 from 2 to 1</span><br></span><span class="token-line" style="color:#000000"><span class="token plain">move 1 from 1 to 2</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div><p>Good luck transforming that into something reasonable :)</p><div class="theme-admonition theme-admonition-tip alert alert--success admonition_LlT9"><div class="admonitionHeading_tbUL"><span class="admonitionIcon_kALy"><svg viewBox="0 0 12 16"><path fill-rule="evenodd" d="M6.5 0C3.48 0 1 2.19 1 5c0 .92.55 2.25 1 3 1.34 2.25 1.78 2.78 2 4v1h5v-1c.22-1.22.66-1.75 2-4 .45-.75 1-2.08 1-3 0-2.81-2.48-5-5.5-5zm3.64 7.48c-.25.44-.47.8-.67 1.11-.86 1.41-1.25 2.06-1.45 3.23-.02.05-.02.11-.02.17H5c0-.06 0-.13-.02-.17-.2-1.17-.59-1.83-1.45-3.23-.2-.31-.42-.67-.67-1.11C2.44 6.78 2 5.65 2 5c0-2.2 2.02-4 4.5-4 1.22 0 2.36.42 3.22 1.19C10.55 2.94 11 3.94 11 5c0 .66-.44 1.78-.86 2.48zM4 14h5c-.23 1.14-1.3 2-2.5 2s-2.27-.86-2.5-2z"></path></svg></span>Fun fact</div><div class="admonitionContent_S0QG"><p>Took me 40 minutes to parse this reasonably, including fighting the compiler.</p></div></div><h3 class="anchor anchorWithStickyNavbar_LWe7" id="solution-4">Solution<a href="#solution-4" class="hash-link" aria-label="Direct link to Solution" title="Direct link to Solution"></a></h3><p>For the initial solution I went with a manual solution (as in <em>I have done all</em>
|
||
<em>the work</em>. Later on I have decided to explore the <code>std</code> and interface of the
|
||
<code>std::vec::Vec</code> and found <a href="https://doc.rust-lang.org/std/vec/struct.Vec.html#method.split_off" target="_blank" rel="noopener noreferrer"><code>split_off</code></a> which takes an index and splits (duh)
|
||
the vector:</p><div class="language-rust codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#ffffff"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-rust codeBlock_bY9V thin-scrollbar"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token keyword" style="color:rgb(0, 0, 255)">let</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(0, 0, 255)">mut</span><span class="token plain"> vec </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token macro property">vec!</span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token number" style="color:rgb(9, 134, 88)">1</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">2</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">3</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token punctuation" style="color:rgb(4, 81, 165)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token keyword" style="color:rgb(0, 0, 255)">let</span><span class="token plain"> vec2 </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> vec</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token function" style="color:rgb(0, 0, 255)">split_off</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token number" style="color:rgb(9, 134, 88)">1</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token macro property">assert_eq!</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">vec</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token number" style="color:rgb(9, 134, 88)">1</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token macro property">assert_eq!</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">vec2</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token number" style="color:rgb(9, 134, 88)">2</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">3</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">;</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div><p>This helped me simplify my solution a lot and also get rid of some <em>edge cases</em>.</p><h2 class="anchor anchorWithStickyNavbar_LWe7" id="day-6-tuning-trouble"><a href="https://adventofcode.com/2022/day/6" target="_blank" rel="noopener noreferrer">Day 6: Tuning Trouble</a><a href="#day-6-tuning-trouble" class="hash-link" aria-label="Direct link to day-6-tuning-trouble" title="Direct link to day-6-tuning-trouble"></a></h2><div class="theme-admonition theme-admonition-info alert alert--info admonition_LlT9"><div class="admonitionHeading_tbUL"><span class="admonitionIcon_kALy"><svg viewBox="0 0 14 16"><path fill-rule="evenodd" d="M7 2.3c3.14 0 5.7 2.56 5.7 5.7s-2.56 5.7-5.7 5.7A5.71 5.71 0 0 1 1.3 8c0-3.14 2.56-5.7 5.7-5.7zM7 1C3.14 1 0 4.14 0 8s3.14 7 7 7 7-3.14 7-7-3.14-7-7-7zm1 3H6v5h2V4zm0 6H6v2h2v-2z"></path></svg></span>tl;dr</div><div class="admonitionContent_S0QG"><p>Finding start of the message in a very weird protocol. Start of the message is
|
||
denoted by <span class="math math-inline"><span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>N</mi></mrow><annotation encoding="application/x-tex">N</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.6833em"></span><span class="mord mathnormal" style="margin-right:0.10903em">N</span></span></span></span></span> unique consecutive characters.</p></div></div><h3 class="anchor anchorWithStickyNavbar_LWe7" id="solution-5">Solution<a href="#solution-5" class="hash-link" aria-label="Direct link to Solution" title="Direct link to Solution"></a></h3><p>A lot of different approaches, knowing that we are dealing with input consisting
|
||
solely of ASCII letters, I bit the bullet and went with sliding window and
|
||
constructing sets from that window, checking if the set is as big as the window.</p><p>One possible optimization could consist of keeping a bit-vector (i.e. <code>usize</code>
|
||
variable) of encountered characters and updating it as we go. However this has
|
||
a different issue and that is removal of the characters from the left side of the
|
||
window. We don't know if the same character is not included later on.</p><p>Other option is to do similar thing, but keeping the frequencies of the letters,
|
||
and again knowing we have only ASCII letters we can optimize by having a vector
|
||
of 26 elements that keeps count for each lowercase letter.</p><h2 class="anchor anchorWithStickyNavbar_LWe7" id="day-7-no-space-left-on-device"><a href="https://adventofcode.com/2022/day/7" target="_blank" rel="noopener noreferrer">Day 7: No Space Left On Device</a><a href="#day-7-no-space-left-on-device" class="hash-link" aria-label="Direct link to day-7-no-space-left-on-device" title="Direct link to day-7-no-space-left-on-device"></a></h2><div class="theme-admonition theme-admonition-info alert alert--info admonition_LlT9"><div class="admonitionHeading_tbUL"><span class="admonitionIcon_kALy"><svg viewBox="0 0 14 16"><path fill-rule="evenodd" d="M7 2.3c3.14 0 5.7 2.56 5.7 5.7s-2.56 5.7-5.7 5.7A5.71 5.71 0 0 1 1.3 8c0-3.14 2.56-5.7 5.7-5.7zM7 1C3.14 1 0 4.14 0 8s3.14 7 7 7 7-3.14 7-7-3.14-7-7-7zm1 3H6v5h2V4zm0 6H6v2h2v-2z"></path></svg></span>tl;dr</div><div class="admonitionContent_S0QG"><p>Let's simulate <a href="https://www.man7.org/linux/man-pages/man1/du.1.html" target="_blank" rel="noopener noreferrer"><code>du</code></a> to get some stats about our file system and then pinpoint
|
||
directories that take a lot of space and should be deleted.</p></div></div><blockquote><p>I was waiting for this moment, and yet it got me!
|
||
<em>imagine me swearing for hours</em></p></blockquote><h3 class="anchor anchorWithStickyNavbar_LWe7" id="solution-6">Solution<a href="#solution-6" class="hash-link" aria-label="Direct link to Solution" title="Direct link to Solution"></a></h3><p>We need to “<em>build</em>” a file system from the input that is given in a following form:</p><div class="codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#ffffff"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-text codeBlock_bY9V thin-scrollbar"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token plain">$ cd /</span><br></span><span class="token-line" style="color:#000000"><span class="token plain">$ ls</span><br></span><span class="token-line" style="color:#000000"><span class="token plain">dir a</span><br></span><span class="token-line" style="color:#000000"><span class="token plain">14848514 b.txt</span><br></span><span class="token-line" style="color:#000000"><span class="token plain">8504156 c.dat</span><br></span><span class="token-line" style="color:#000000"><span class="token plain">dir d</span><br></span><span class="token-line" style="color:#000000"><span class="token plain">$ cd a</span><br></span><span class="token-line" style="color:#000000"><span class="token plain">$ ls</span><br></span><span class="token-line" style="color:#000000"><span class="token plain">dir e</span><br></span><span class="token-line" style="color:#000000"><span class="token plain">29116 f</span><br></span><span class="token-line" style="color:#000000"><span class="token plain">2557 g</span><br></span><span class="token-line" style="color:#000000"><span class="token plain">62596 h.lst</span><br></span><span class="token-line" style="color:#000000"><span class="token plain">$ cd e</span><br></span><span class="token-line" style="color:#000000"><span class="token plain">$ ls</span><br></span><span class="token-line" style="color:#000000"><span class="token plain">584 i</span><br></span><span class="token-line" style="color:#000000"><span class="token plain">$ cd ..</span><br></span><span class="token-line" style="color:#000000"><span class="token plain">$ cd ..</span><br></span><span class="token-line" style="color:#000000"><span class="token plain">$ cd d</span><br></span><span class="token-line" style="color:#000000"><span class="token plain">$ ls</span><br></span><span class="token-line" style="color:#000000"><span class="token plain">4060174 j</span><br></span><span class="token-line" style="color:#000000"><span class="token plain">8033020 d.log</span><br></span><span class="token-line" style="color:#000000"><span class="token plain">5626152 d.ext</span><br></span><span class="token-line" style="color:#000000"><span class="token plain">7214296 k</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div><p>There are few ways in which you can achieve this and also you can assume some
|
||
preconditions, but why would we do that, right? :)</p><p>You can “slap” this in either <a href="https://doc.rust-lang.org/std/collections/struct.HashMap.html" target="_blank" rel="noopener noreferrer"><code>HashMap</code></a> or <a href="https://doc.rust-lang.org/std/collections/struct.BTreeMap.html" target="_blank" rel="noopener noreferrer"><code>BTreeMap</code></a> and call it a day.
|
||
And that would be boring…</p><div class="theme-admonition theme-admonition-tip alert alert--success admonition_LlT9"><div class="admonitionHeading_tbUL"><span class="admonitionIcon_kALy"><svg viewBox="0 0 12 16"><path fill-rule="evenodd" d="M6.5 0C3.48 0 1 2.19 1 5c0 .92.55 2.25 1 3 1.34 2.25 1.78 2.78 2 4v1h5v-1c.22-1.22.66-1.75 2-4 .45-.75 1-2.08 1-3 0-2.81-2.48-5-5.5-5zm3.64 7.48c-.25.44-.47.8-.67 1.11-.86 1.41-1.25 2.06-1.45 3.23-.02.05-.02.11-.02.17H5c0-.06 0-.13-.02-.17-.2-1.17-.59-1.83-1.45-3.23-.2-.31-.42-.67-.67-1.11C2.44 6.78 2 5.65 2 5c0-2.2 2.02-4 4.5-4 1.22 0 2.36.42 3.22 1.19C10.55 2.94 11 3.94 11 5c0 .66-.44 1.78-.86 2.48zM4 14h5c-.23 1.14-1.3 2-2.5 2s-2.27-.86-2.5-2z"></path></svg></span>tip</div><div class="admonitionContent_S0QG"><p><code>BTreeMap</code> is quite fitting for this, don't you think?</p></div></div><p>I always wanted to try allocation on heap in Rust, so I chose to implement a tree.
|
||
I fought with the <code>Box<T></code> for some time and was losing…</p><p>Then I looked up some implementations of trees or linked lists and decided to try
|
||
<code>Rc<Cell<T>></code>. And I got my <em>ass whopped</em> by the compiler once again. /o\</p><div class="theme-admonition theme-admonition-tip alert alert--success admonition_LlT9"><div class="admonitionHeading_tbUL"><span class="admonitionIcon_kALy"><svg viewBox="0 0 12 16"><path fill-rule="evenodd" d="M6.5 0C3.48 0 1 2.19 1 5c0 .92.55 2.25 1 3 1.34 2.25 1.78 2.78 2 4v1h5v-1c.22-1.22.66-1.75 2-4 .45-.75 1-2.08 1-3 0-2.81-2.48-5-5.5-5zm3.64 7.48c-.25.44-.47.8-.67 1.11-.86 1.41-1.25 2.06-1.45 3.23-.02.05-.02.11-.02.17H5c0-.06 0-.13-.02-.17-.2-1.17-.59-1.83-1.45-3.23-.2-.31-.42-.67-.67-1.11C2.44 6.78 2 5.65 2 5c0-2.2 2.02-4 4.5-4 1.22 0 2.36.42 3.22 1.19C10.55 2.94 11 3.94 11 5c0 .66-.44 1.78-.86 2.48zM4 14h5c-.23 1.14-1.3 2-2.5 2s-2.27-.86-2.5-2z"></path></svg></span>tip</div><div class="admonitionContent_S0QG"><p><code>Box<T></code> represents a dynamically allocated memory on heap. It is a single pointer,
|
||
you can imagine this as <code>std::unique_ptr<T></code> in C++.</p><p><code>Rc<T></code> represents a dynamically allocated memory on heap. On top of that it is
|
||
<em>reference counted</em> (that's what the <code>Rc</code> stands for). You can imagine this as
|
||
<code>std::shared_ptr<T></code> in C++.</p><p>Now the fun stuff. Neither of them lets you <strong>mutate</strong> the contents of the memory.</p><p><code>Cell<T></code> allows you to mutate the memory. Can be used reasonably with types that
|
||
can be copied, because the memory safety is guaranteed by copying the contents
|
||
when there is more than one <strong>mutable</strong> reference to the memory.</p><p><code>RefCell<T></code> is similar to the <code>Cell<T></code>, but the borrowing rules (how many mutable
|
||
references are present) are checked dynamically.</p><p>So in the end, if you want something like <code>std::shared_ptr<T></code> in Rust, you want
|
||
to have <code>Rc<RefCell<T>></code>.</p></div></div><p>So, how are we going to represent the file system then? We will use an enumeration,
|
||
hehe, which is an algebraic data type that can store some stuff in itself 😩</p><div class="language-rust codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#ffffff"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-rust codeBlock_bY9V thin-scrollbar"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token keyword" style="color:rgb(0, 0, 255)">type</span><span class="token plain"> </span><span class="token type-definition class-name" style="color:rgb(38, 127, 153)">FileHandle</span><span class="token plain"> </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token class-name" style="color:rgb(38, 127, 153)">Rc</span><span class="token operator" style="color:rgb(0, 0, 0)"><</span><span class="token class-name" style="color:rgb(38, 127, 153)">RefCell</span><span class="token operator" style="color:rgb(0, 0, 0)"><</span><span class="token class-name" style="color:rgb(38, 127, 153)">AocFile</span><span class="token operator" style="color:rgb(0, 0, 0)">>></span><span class="token punctuation" style="color:rgb(4, 81, 165)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token attribute attr-name" style="color:rgb(255, 0, 0)">#[derive(Debug)]</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token keyword" style="color:rgb(0, 0, 255)">enum</span><span class="token plain"> </span><span class="token type-definition class-name" style="color:rgb(38, 127, 153)">AocFile</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">{</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> </span><span class="token class-name" style="color:rgb(38, 127, 153)">File</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token keyword" style="color:rgb(0, 0, 255)">usize</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> </span><span class="token class-name" style="color:rgb(38, 127, 153)">Directory</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token class-name" style="color:rgb(38, 127, 153)">BTreeMap</span><span class="token operator" style="color:rgb(0, 0, 0)"><</span><span class="token class-name" style="color:rgb(38, 127, 153)">String</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token class-name" style="color:rgb(38, 127, 153)">FileHandle</span><span class="token operator" style="color:rgb(0, 0, 0)">></span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token punctuation" style="color:rgb(4, 81, 165)">}</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div><p>Let's go over it! <code>FileHandle</code> represents dynamically allocated <code>AocFile</code>, not
|
||
much to discuss. What does the <code>#[derive(Debug)]</code> do though? It lets us to print
|
||
out the value of that enumeration, it's derived, so it's not as good as if we had
|
||
implemented it ourselves, but it's good enough for debugging, hence the name.</p><p>Now to the fun part! <code>AocFile</code> value can be represented in two ways:</p><ul><li><code>File(usize)</code>, e.g. <code>AocFile::File(123)</code> and we can pattern match it, if we
|
||
need to</li><li><code>Directory(BTreeMap<String, FileHandle>)</code> will represent the directory and will
|
||
contain map matching the name of the files (or directories) within to their
|
||
respective file handles</li></ul><p>I will omit the details about constructing this file system, cause there are a lot
|
||
of technicalities introduced by the nature of the input. However if you are
|
||
interested, you can have a look at my solution.</p><p>We need to find small enough directories and also find the smallest directory that
|
||
will free enough space. Now the question is, how could we do that. And there are
|
||
multiple ways I will describe.</p><p>I have chosen to implement <a href="https://en.wikipedia.org/wiki/Catamorphism#Tree_fold" target="_blank" rel="noopener noreferrer"><em>tree catamorphism</em></a> 😩. It is basically a fold
|
||
over a tree data structure. We descent down into the leaves and propagate computed
|
||
results all the way to the root. You can also notice that this approach is very
|
||
similar to <em>dynamic programming</em>, we find overlapping sections of the computation
|
||
and try to minimize the additional work (in this case: we need to know sizes of
|
||
our descendants, but we have already been there).</p><p>Another approach that has been suggested to me few days later is running DFS on
|
||
the graph. And, funnily enough, we would still need to combine what we found in
|
||
the branches where we descent. So in the end, it would work very similarly to my
|
||
solution.</p><p>One of the more exotic options would be precomputing the required information at
|
||
the same time as parsing. That could be done by adding additional fields to the
|
||
nodes which would allow storing such information and updating it as we construct
|
||
the file system.</p><h2 class="anchor anchorWithStickyNavbar_LWe7" id="post-mortem">Post Mortem<a href="#post-mortem" class="hash-link" aria-label="Direct link to Post Mortem" title="Direct link to Post Mortem"></a></h2><p>Things that have been brought up in the discussion later on.</p><h3 class="anchor anchorWithStickyNavbar_LWe7" id="rct-vs-rcrefcellt"><code>Rc<T></code> vs <code>Rc<RefCell<T>></code><a href="#rct-vs-rcrefcellt" class="hash-link" aria-label="Direct link to rct-vs-rcrefcellt" title="Direct link to rct-vs-rcrefcellt"></a></h3><p>It has been brought up that I have a contradicting statement regarding the
|
||
dynamically allocated memory. Specifically:</p><ul><li>You can imagine <code>Rc<T></code> as an <code>std::shared_ptr<T></code> (in C++)</li><li>When you want an equivalent of <code>std::shared_ptr<T></code>, you want to use
|
||
<code>Rc<RefCell<T>></code></li></ul><p>Now, in Rust it is a bit more complicated, because the type that represents the
|
||
“shared pointer” is <code>Rc<T></code>. What <code>RefCell<T></code> does is making sure that there is
|
||
only one “owner” of a mutable reference at a time (and dynamically, as opposed
|
||
to the <code>Cell<T></code>).</p><p>Therefore to be precise and correct about the equivalents of <code>std::shared_ptr<T></code>
|
||
in Rust, we can say that</p><ul><li><code>Rc<T></code> is an equivalent of a <code>const std::shared_ptr<T></code>,</li><li>and <code>Rc<RefCell<T>></code> is an equivalent of a <code>std::shared_ptr<T></code>.</li></ul><p>You can easily see that they only differ in the mutability. (And even that is not
|
||
as simple as it seems, because there is also <code>Cell<T></code>)</p></div><footer class="row docusaurus-mt-lg blogPostFooterDetailsFull_mRVl"><div class="col"><b>Tags:</b><ul class="tags_jXut padding--none margin-left--sm"><li class="tag_QGVx"><a class="tag_zVej tagRegular_sFm0" href="/blog/tags/advent-of-code">advent-of-code</a></li><li class="tag_QGVx"><a class="tag_zVej tagRegular_sFm0" href="/blog/tags/advent-of-code-2022">advent-of-code-2022</a></li><li class="tag_QGVx"><a class="tag_zVej tagRegular_sFm0" href="/blog/tags/rust">rust</a></li></ul></div><div class="col margin-top--sm"><a href="https://gitlab.com/mfocko/blog/tree/main/blog/aoc-2022/01-week-1.md" target="_blank" rel="noreferrer noopener" class="theme-edit-this-page"><svg fill="currentColor" height="20" width="20" viewBox="0 0 40 40" class="iconEdit_Z9Sw" aria-hidden="true"><g><path d="m34.5 11.7l-3 3.1-6.3-6.3 3.1-3q0.5-0.5 1.2-0.5t1.1 0.5l3.9 3.9q0.5 0.4 0.5 1.1t-0.5 1.2z m-29.5 17.1l18.4-18.5 6.3 6.3-18.4 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class="table-of-contents__link toc-highlight">Day 2: Rock Paper Scissors</a><ul><li><a href="#solution-1" class="table-of-contents__link toc-highlight">Solution</a></li></ul></li><li><a href="#day-3-rucksack-reorganization" class="table-of-contents__link toc-highlight">Day 3: Rucksack Reorganization</a><ul><li><a href="#solution-2" class="table-of-contents__link toc-highlight">Solution</a></li></ul></li><li><a href="#day-4-camp-cleanup" class="table-of-contents__link toc-highlight">Day 4: Camp Cleanup</a><ul><li><a href="#solution-3" class="table-of-contents__link toc-highlight">Solution</a></li></ul></li><li><a href="#day-5-supply-stacks" class="table-of-contents__link toc-highlight">Day 5: Supply Stacks</a><ul><li><a href="#solution-4" class="table-of-contents__link toc-highlight">Solution</a></li></ul></li><li><a href="#day-6-tuning-trouble" class="table-of-contents__link toc-highlight">Day 6: Tuning Trouble</a><ul><li><a href="#solution-5" class="table-of-contents__link toc-highlight">Solution</a></li></ul></li><li><a href="#day-7-no-space-left-on-device" class="table-of-contents__link toc-highlight">Day 7: No Space Left On Device</a><ul><li><a href="#solution-6" class="table-of-contents__link toc-highlight">Solution</a></li></ul></li><li><a href="#post-mortem" class="table-of-contents__link toc-highlight">Post Mortem</a><ul><li><a href="#rct-vs-rcrefcellt" class="table-of-contents__link toc-highlight"><code>Rc<T></code> vs <code>Rc<RefCell<T>></code></a></li></ul></li></ul></div></div></div></div></div><footer class="footer footer--dark"><div class="container container-fluid"><div class="row footer__links"><div class="col footer__col"><div class="footer__title">Git</div><ul class="footer__items clean-list"><li class="footer__item"><a href="https://github.com/mfocko" target="_blank" rel="noopener noreferrer" class="footer__link-item">GitHub<svg width="13.5" height="13.5" aria-hidden="true" viewBox="0 0 24 24" class="iconExternalLink_nPIU"><path 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