LeetCode--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.

思路：动态规划法。这一题也基本和前两题相同，就是相当于每一个格子上的数字代表权值，除了第1行和第1列，就要考虑从上面来还是从左边来的路径最短。

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