Minimum Path Sum Given a m x n grid filled with non-negative numbers, find a path from top left to bottom right which minimizes the sum of all numbers along its path. Note: You can only move either down or right at any point in time. SOLUTION 1: 相当基础…
引言 二维动态规划中最常见的是棋盘型二维动态规划. 即 func(i, j) 往往只和 func(i-1, j-1), func(i-1, j) 以及 func(i, j-1) 有关 这种情况下,时间复杂度 O(n*n),空间复杂度往往可以优化为O(n) 例题  1 Minimum Path Sum  Given a m x n grid filled with non-negative numbers, find a path from top left to bottom right whi…
题意: 给一个n*m的矩阵,每次可以往下或右走,经过的格子中的数字之和就是答案了,答案最小为多少? 思路: 比较水,只是各种空间利用率而已. 如果可以在原空间上作修改. class Solution { public: int minPathSum(vector<vector<int>>& grid) { ; ; ; j<=m; j++) grid[][j]+=grid[][j-]; ; i<=n; i++) { grid[i][]+=grid[i-][]; ;…
一个m*n的表格,每个格子有一个非负数,求从左上到右下最短的路径值 和62,63两个值是同一个思路,建立dp表,记录每个位置到右下角的最短路径的值 class Solution(object): def minPathSum(self, grid): m,n = len(grid),len(grid[0]) flag = [[0 for i in range(n)] for j in range(m)] flag[m-1][n-1] = grid[m-1][n-1] for i in range…
Given a m x n grid filled with non-negative numbers, find a path from top left to bottom right which minimizes the sum of all numbers along its path. Note: You can only move either down or right at any point in time. 做这题之前,建议先看一下Leetcode Triangle 这题看…
原题地址:https://oj.leetcode.com/problems/minimum-path-sum/ 题意: Given a m x n grid filled with non-negative numbers, find a path from top left to bottom right which minimizes the sum of all numbers along its path. Note: You can only move either down or r…
Given a m x n grid filled with non-negative numbers, find a path from top left to bottom right which minimizes the sum of all numbers along its path. Note: You can only move either down or right at any point in time. 这道题跟之前那道Dungeon Game 地牢游戏 没有什么太大的…
题目链接 Given a m x n grid filled with non-negative numbers, find a path from top left to bottom right which minimizes the sum of all numbers along its path. Note: You can only move either down or right at any point in time. 典型的动态规划问题. 设dp[i][j]表示从左上角到g…
Unique Paths https://oj.leetcode.com/problems/unique-paths/ A robot is located at the top-left corner of a m x n grid (marked 'Start' in the diagram below). The robot can only move either down or right at any point in time. The robot is trying to rea…
Leetcode之动态规划(DP)专题-64. 最小路径和(Minimum Path Sum) 给定一个包含非负整数的 m x n 网格,请找出一条从左上角到右下角的路径,使得路径上的数字总和为最小. 说明:每次只能向下或者向右移动一步. 示例: 输入: [   [1,3,1], [1,5,1], [4,2,1] ] 输出: 7 解释: 因为路径 1→3→1→1→1 的总和最小. 找从左上角0,0到右下角的最短路径. DP:我们每个点(x,y)都可以表示为dp[x][y] = max( grid…