64. Minimum Path Sum

problem：

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.

和前面两题思路一致，分类for循环即可，判断左边和上边哪个小，就加上哪个。

class Solution {public:    int minPathSum(vector<vector<int>>& grid) {        int m = grid.size();        int n = grid[0].size();        int test;        vector<vector<int> > result(m, vector<int>(n,0));        result[0][0] = grid[0][0];        for(int i=1; i<m; i++)        {            result[i][0] = result[i-1][0] + grid[i][0];            test = result[i][0];        }        for(int j=1; j<n; j++)        {            result[0][j] = result[0][j-1] + grid[0][j];            test = result[0][j];        }        for(int i=1; i<m; i++)        {            for(int j=1; j<n; j++)            {                int temp = min(result[i-1][j], result[i][j-1]);                result[i][j] = temp + grid[i][j];                test = result[i][j];            }        }        return result[m-1][n-1];    }};