64. 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.*/#include <iostream>#include <stdio.h>#include <vector>using namespace std;/*   dp[i][j] = dp[i][j-1] < dp[i-1][j] ? grid[i][j]+dp[i][j-1] : grid[i][j]+dp[i-1][j];   如果用一个一位数组来存储中间值，需要单独处理第一行与第一列*/class Solution {public:    int minPathSum(vector<vector<int>>& grid) {        int m=grid.size(),n=grid[0].size();vector<int> dp(n+1,0);for(int i=0;i<m;i++)for(int j=1;j<=n;j++){if(i==0) dp[j]=dp[j-1]+grid[i][j-1];else if(j==1) dp[j]=dp[j]+grid[i][j-1];else dp[j] = dp[j-1] < dp[j] ? dp[j-1]+grid[i][j-1] : dp[j]+grid[i][j-1];}return dp[n];    }};int main(){Solution mys;vector<vector<int> >grid={{1,2},{1,1}};cout<<mys.minPathSum(grid)<<endl;return 0;}