- Problem

1572. Matrix Diagonal Sum

- 내 풀이

class Solution:
    def diagonalSum(self, mat: List[List[int]]) -> int:
        N = len(mat)
        answer = sum(mat[i][i] + mat[i][N-i-1] for i in range(N))
        return answer if not N % 2 else answer - mat[N//2][N//2]

- 결과

• 시간 복잡도: O(N)
• 공간 복잡도: O(1)