1572. Matrix Diagonal Sum 链接到标题 对角线之和，需要注意当行为奇数和偶数时候的去重处理。class Solution: def diagonalSum(self, mat: List[List[int]]) -> int: n = len(mat) if n == 1: return mat[0][0] ans = 0 for i in range(n): if i != n-1-i: ans += mat[i][i] ans += mat[i][n-1-i] else: ans += mat[i][i] return ans 1576. Replace All ?……