leetcode:Minimum Path Sum(路线上元素和的最小值)
题目: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.
题意从左上到右下,所有可能的路径中,求经过的元素和最小值。
动态规划基础题了,dp每个状态由左边或者上边的值中,较小的值与当前状态的值相加得到。
注意考虑边界情况就行了。
int dp[1000][1000]; class Solution { public: int minPathSum(vector<vector<int> > &grid) { int rows=grid.size(); if(rows==0)return 0; int cols=grid[0].size(); if(cols==0)return 0; memset(dp,0,sizeof(dp)); for(int i=0;i<rows;++i) { for(int j=0;j<cols;++j) { if(i==0&&j==0)dp[0][0]=grid[0][0]; else if(j==0)dp[i][0]=dp[i-1][0]+grid[i][0]; else if(i==0)dp[0][j]=dp[0][j-1]+grid[0][j]; else dp[i][j]=min(dp[i-1][j],dp[i][j-1])+grid[i][j]; } } return dp[rows-1][cols-1]; } };
补充:软件开发 , C++ ,