The correct, optimal and working solution for programming question minimum-path-sum on leetcode

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