Problem URL: Toeplitz matrix

We will iterate over the rows and columns and compare diagonally adjacent elements. If they are not equal, we can return false. If we reach the end of the loop, we can return true.

class Solution:
    def isToeplitzMatrix(self, matrix: List[List[int]]) -> bool:
        for i in range(len(matrix)):
            for j in range(len(matrix[0])):
                if i > 0 and j > 0 and matrix[i][j] != matrix[i-1][j-1]:
                    return False
        return True

Time complexity: O(n)
Space complexity: O(1)

Here is the solution in more pythonic way:

class Solution:
    def isToeplitzMatrix(self, matrix: List[List[int]]) -> bool:
        return all(r1[:-1] == r2[1:] for r1, r2 in zip(matrix, matrix[1:]))