LeetCode64 Minimum Path Sum 最小路径和

问题描述：
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.

Example:

Input:
[
  [1,3,1],
  [1,5,1],
  [4,2,1]
]
Output: 7

Explanation: Because the path 1→3→1→1→1 minimizes the sum.
题源：here；完整实现：here
思路：
使用和第63题，第62题相同的动态规划策略，但需要选择累加更小的路径，代码如下：

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

        return grid[m - 1][n - 1];}};

贴出运行结果纪念一下：