blog/assets/js/9b91a88c.5685ebf2.js

"use strict";(self.webpackChunkfi=self.webpackChunkfi||[]).push([[2545],{19466:(e,n,o)=>{o.r(n),o.d(n,{assets:()=>l,contentTitle:()=>s,default:()=>m,frontMatter:()=>r,metadata:()=>a,toc:()=>d});var i=o(85893),t=o(11151);const r={id:"pyramid-slide-down",slug:"/recursion/pyramid-slide-down",title:"Introduction to dynamic programming",description:"Solving a problem in different ways.\n",tags:["java","recursion","exponential","greedy","dynamic-programming","top-down-dp","bottom-up-dp"],last_update:{date:new Date("2023-08-17T00:00:00.000Z")}},s=void 0,a={id:"recursion/2023-08-17-pyramid-slide-down/pyramid-slide-down",title:"Introduction to dynamic programming",description:"Solving a problem in different ways.\n",source:"@site/algorithms/04-recursion/2023-08-17-pyramid-slide-down/index.md",sourceDirName:"04-recursion/2023-08-17-pyramid-slide-down",slug:"/recursion/pyramid-slide-down",permalink:"/algorithms/recursion/pyramid-slide-down",draft:!1,unlisted:!1,editUrl:"https://github.com/mfocko/blog/tree/main/algorithms/04-recursion/2023-08-17-pyramid-slide-down/index.md",tags:[{label:"java",permalink:"/algorithms/tags/java"},{label:"recursion",permalink:"/algorithms/tags/recursion"},{label:"exponential",permalink:"/algorithms/tags/exponential"},{label:"greedy",permalink:"/algorithms/tags/greedy"},{label:"dynamic-programming",permalink:"/algorithms/tags/dynamic-programming"},{label:"top-down-dp",permalink:"/algorithms/tags/top-down-dp"},{label:"bottom-up-dp",permalink:"/algorithms/tags/bottom-up-dp"}],version:"current",lastUpdatedAt:1692230400,formattedLastUpdatedAt:"Aug 17, 2023",frontMatter:{id:"pyramid-slide-down",slug:"/recursion/pyramid-slide-down",title:"Introduction to dynamic programming",description:"Solving a problem in different ways.\n",tags:["java","recursion","exponential","greedy","dynamic-programming","top-down-dp","bottom-up-dp"],last_update:{date:"2023-08-17T00:00:00.000Z"}},sidebar:"autogeneratedBar",previous:{title:"Solution to the problem",permalink:"/algorithms/recursion/karel/solution"},next:{title:"Na\xefve solution",permalink:"/algorithms/recursion/pyramid-slide-down/naive"}},l={},d=[{value:"Problem",id:"problem",level:2},{value:"Solving the problem",id:"solving-the-problem",level:2}];function c(e){const n={a:"a",admonition:"admonition",code:"code",em:"em",h2:"h2",li:"li",ol:"ol",p:"p",pre:"pre",section:"section",sup:"sup",...(0,t.a)(),...e.components};return(0,i.jsxs)(i.Fragment,{children:[(0,i.jsx)(n.p,{children:"In this series we will try to solve one problem in different ways."}),"\n",(0,i.jsx)(n.h2,{id:"problem",children:"Problem"}),"\n",(0,i.jsxs)(n.p,{children:["The problem we are going to solve is one of ",(0,i.jsx)(n.em,{children:"CodeWars"})," katas and is called\n",(0,i.jsx)(n.a,{href:"https://www.codewars.com/kata/551f23362ff852e2ab000037",children:"Pyramid Slide Down"}),"."]}),"\n",(0,i.jsxs)(n.p,{children:["We are given a 2D array of integers and we are to find the ",(0,i.jsx)(n.em,{children:"slide down"}),".\n",(0,i.jsx)(n.em,{children:"Slide down"})," is a maximum sum of consecutive numbers from the top to the bottom."]}),"\n",(0,i.jsx)(n.p,{children:"Let's have a look at few examples. Consider the following pyramid:"}),"\n",(0,i.jsx)(n.pre,{children:(0,i.jsx)(n.code,{children:"   3\n  7 4\n 2 4 6\n8 5 9 3\n"})}),"\n",(0,i.jsx)(n.p,{children:"This pyramid has following slide down:"}),"\n",(0,i.jsx)(n.pre,{children:(0,i.jsx)(n.code,{children:"   *3\n  *7 4\n 2 *4 6\n8 5 *9 3\n"})}),"\n",(0,i.jsxs)(n.p,{children:["And its value is ",(0,i.jsx)(n.code,{children:"23"}),"."]}),"\n",(0,i.jsxs)(n.p,{children:["We can also have a look at a ",(0,i.jsx)(n.em,{children:"bigger"})," example:"]}),"\n",(0,i.jsx)(n.pre,{children:(0,i.jsx)(n.code,{children:"                75\n               95 64\n              17 47 82\n             18 35 87 10\n            20  4 82 47 65\n            19  1 23  3 34\n         88  2 77 73  7 63 67\n        99 65  4 28  6 16 70 92\n       41 41 26 56 83 40 80 70 33\n      41 48 72 33 47 32 37 16 94 29\n     53 71 44 65 25 43 91 52 97 51 14\n    70 11 33 28 77 73 17 78 39 6