766. Toeplitz Matrix - cocoder39/coco39_LC GitHub Wiki

766. Toeplitz Matrix

class Solution:
    def isToeplitzMatrix(self, matrix: List[List[int]]) -> bool:
        m, n = len(matrix), len(matrix[0])
        diagonals = {}
        for i in range(m):
            for j in range(n):
                diagonal = i - j
                if diagonal not in diagonals:
                    diagonals[diagonal] = matrix[i][j]
                elif diagonals[diagonal] != matrix[i][j]:
                    return False
        return True