advent-of-code/2023
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day(12): move the mutability into the function

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Signed-off-by: Matej Focko <mfocko@redhat.com>
This commit is contained in:
Matej Focko 2023-12-12 15:28:38 +01:00
parent dc2df6d7fb
commit 20de5928c2
Signed by: mfocko
GPG key ID: 7C47D46246790496
1 changed files with 20 additions and 25 deletions
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45
src/bin/day12.rs
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@ -30,11 +30,7 @@ impl FromStr for Row {
}
#[memoize]
fn arrangements(
mut map: VecDeque<char>,
mut damaged: VecDeque<usize>,
mut in_damaged: bool,
) -> usize {
fn arrangements(map: VecDeque<char>, damaged: VecDeque<usize>, in_damaged: bool) -> usize {
// all damaged have been placed
if damaged.is_empty() {
return if map.iter().all(|&c| c == '.' || c == '?') {
@ -44,6 +40,10 @@ fn arrangements(
};
}
let mut map = map.clone();
let mut damaged = damaged.clone();
let mut in_damaged = in_damaged;
// skip the functional
while let Some('.') = map.front() {
if in_damaged {
@ -60,43 +60,38 @@ fn arrangements(
match map[0] {
'?' => {
map[0] = '#';
let as_non_functional = arrangements(map.clone(), damaged.clone(), true);
map[0] = '.';
let as_functional = if !in_damaged {
arrangements(map, damaged, false)
arrangements(map.clone(), damaged.clone(), false)
} else {
0
};
map[0] = '#';
let as_non_functional = arrangements(map, damaged, true);
as_functional + as_non_functional
}
'#' if damaged.is_empty() => 0,
'#' => {
damaged[0] -= 1;
map.pop_front();
if damaged[0] == 0 {
if 1 < map.len() && map[1] == '#' {
damaged.pop_front();
if let Some(&'#') = map.front() {
0
} else if 1 < map.len() {
map[1] = '.';
arrangements(
map.iter().cloned().skip(1).collect(),
damaged.iter().cloned().skip(1).collect(),
false,
)
} else if !map.is_empty() {
map[0] = '.';
arrangements(map, damaged, false)
} else {
let result = arrangements(
map.iter().cloned().skip(2).collect(),
damaged.iter().cloned().skip(1).collect(),
false,
);
result
map.pop_front();
arrangements(map, damaged, false)
}
} else {
let result = arrangements(map.iter().cloned().skip(1).collect(), damaged, true);
result
arrangements(map, damaged, true)
}
}
_ => unreachable!(),