class Solution {public:    int minPathSum(vector<vector<int> > &grid) {        // dp[i][j] = min(dp[i-1][j] + dp[i][j], dp[i][j-1] + dp[i][j]);        int n = grid.size(); // ver        if (n == 0) return 0;        int m = grid[0].size();// hor        if (m == 0) return 0;        //    Init        vector<vector<unsigned long>> dp;        dp.resize(n + 1);         for (int i = 0; i < dp.size(); i++)            dp[i].resize(m + 1);        std::fill(dp[0].begin(), dp[0].end(), std::numeric_limits<int>::max());        for (int i = 0; i <= n; i++) dp[i][0] = std::numeric_limits<int>::max();        dp[1][1] = grid[0][0];        for (int i = 1; i <= n; i ++)        for (int j = 1; j <= m; j++)        {            if (i == 1 && j == 1) continue;            dp[i][j] = std::min(                grid[i - 1][j - 1] + dp[i - 1][j],                 grid[i - 1][j - 1] + dp[i][j - 1]                );        }        return dp[n][m];    }};