Leetcode 1572. Matrix Diagonal Sum [Python]

注意行列数为奇数时，需要减去中心的位置的值，因为其被加和了两次。

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