64. Minimum Path Sum

简单DP问题

class Solution {
public:
    int minPathSum(vector<vector<int>>& grid) {
        if(grid.size()==0)
            return 0;

        int m=grid.size();
        int n=grid[0].size();

        vector<vector<int>> dp;
        vector<int> temp(n,0);
        for(int i=0;i<m;i++)
            dp.push_back(temp);

        for(int i=0;i<m;i++)
        {
            for(int j=0;j<n;j++)
            {
                if(i-1>=0&&j-1>=0)
                    dp[i][j]=min(dp[i-1][j],dp[i][j-1])+grid[i][j];
                else if(i-1<0&&j-1>=0)
                    dp[i][j]=dp[i][j-1]+grid[i][j];
                else if(i-1>=0&&j-1<0)
                    dp[i][j]=dp[i-1][j]+grid[i][j];
                else
                    dp[i][j]=grid[i][j];
            }
        }
        return dp[m-1][n-1];

    }
};