Minimum Path Sum

这道题很简单了，和前面
Unique path的那两道题差不多。

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

path[i][j]=min(path[i][j-1]+grid[i][j],path[i-1][j]+grid[i][j]); 

                            } 
                                 } 

return path.back().back();                   } 
};

 Runtime: 8 ms, faster than 58.99% of C++ online submissions for Minimum Path Sum.