2025-08-03 13:21:01 +0000 UTC

class Solution:
    def diagonalSum(self, mat: List[List[int]]) -> int:
        length = len(mat)
        res = 0
        for i in range(length):
            row1, col1 = i, i
            row2, col2 = i, length - i - 1
            res += mat[row1][col1]
            if row2 != row1 or col2 != col1:
                res += mat[row2][col2]
        return res