LeetCode_Minimum Path Sum

iven 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.

　　动态规划： grid[i][j] += min(grid[i-1][j], grid[i][j-1])

class Solution {
public:
    int minPathSum(vector<vector<int> > &grid) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        int m = grid.size();
        int n = grid[0].size();
        
        for(int i = 1; i< n ; i++)
             grid[0][i] += grid[0][i-1];
        for(int j = 1; j < m; j++)
            grid[j][0] += grid[j-1][0];
            
        for( int i = 1; i < m ; i++)
            for( int j = 1; j < n ; j++)
            {
                int temp = grid[i-1][j] < grid[i][j-1] ? grid[i-1][j] : grid[i][j-1];
                grid[i][j] +=temp;
            }
        
        return grid[m-1][n-1];
    }
};