Leetcode 64 Minimum Path Sum

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