leetcode - Minimum Path Sum

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.

//利用dp解决，动态转移方程为：// dp[i][j] = min(dp[i-1][j],dp[i][j-1]) + grid[i][j].class Solution {public:    int minPathSum(std::vector<std::vector<int> > &grid) {        std::vector<std::vector<int>> dp(grid.size(),std::vector<int>(grid[0].size(),0));dp[0][0] = grid[0][0];for (int i = 1; i < grid.size(); i++){dp[i][0] = dp[i-1][0] + grid[i][0];}for (int i = 1; i < grid[0].size(); i++){dp[0][i] = dp[0][i-1] + grid[0][i];}for (int i = 1; i < grid.size(); i++){for (int j = 1; j < grid[0].size(); j++){dp[i][j] = std::min(dp[i-1][j],dp[i][j-1]) + grid[i][j];}}return dp[grid.size()-1][grid[0].size()-1];    }};