LeetCode/1572_Matrix_Diagonal_Sum at master · KnowledgeCenterYoutube/LeetCode · GitHub

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Leetcode 1572: Matrix Diagonal Sum
Detailed video explanation: https://youtu.be/5yF2HkQXuSo
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C++:
----
class Solution {
public:
    int diagonalSum(vector<vector<int>>& mat) {
        int n = mat.size();
        int sum = 0;
        for(int i = 0; i < n; ++i)
            sum += mat[i][i] + mat[i][n-i-1];
        if(n % 2) sum -= mat[n/2][n/2];

        return sum;
    }
};


Java:
-----
class Solution {
    public int diagonalSum(int[][] mat) {
        int n = mat.length;
        int sum = 0;
        for(int i = 0; i < n; ++i)
            sum += mat[i][i] + mat[i][n-i-1];
        if(n % 2 == 1) sum -= mat[n/2][n/2];

        return sum;
    }
}


Python3:
-------
class Solution:
    def diagonalSum(self, mat: List[List[int]]) -> int:
        n, sum = len(mat), 0
        for i in range(n):
            sum += mat[i][i] + mat[i][n-i-1]
        if n % 2 == 1: sum -= mat[n//2][n//2]

        return sum