leetcode：Minimum Path Sum（路线上元素和的最小值）

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





 > &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