10 lines C++ DP


  • 0

    There are only 2 directions to reach a given cell[i][j], either from above it or from left,

    • dp[i][j - 1] (min path sum from its left)

    • dp[i - 1][j] (min path sum from its above)

    Min path = min(min path sum from its left, min path sum from its above) + Current Value

    min{ dp[i][j - 1], dp[i - 1][j] } + grid[i][j];

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

Log in to reply
 

Looks like your connection to LeetCode Discuss was lost, please wait while we try to reconnect.