leetcode_minimum_path_sum

发表于

难度：Medium

解题思路：

ret[i][j] = min(ret[i-1][j]+grid[i][j],ret[i][j-1]+grid[i][i])
注意边界的初始化。

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

运行结果：12ms，超过46.41%