766. Toeplitz Matrix Toeplitz矩阵

Posted 2020-10-21 Long Long Journey

A matrix is Toeplitz if every diagonal from top-left to bottom-right has the same element.

Now given an M x N matrix, return True if and only if the matrix is Toeplitz.

Example 1:

Input: matrix = [[1,2,3,4],[5,1,2,3],[9,5,1,2]]
Output: True
Explanation:
1234
5123
9512

In the above grid, the diagonals are "[9]", "[5, 5]", "[1, 1, 1]", "[2, 2, 2]", "[3, 3]", "[4]", and in each diagonal all elements are the same, so the answer is True.

Example 2:

Input: matrix = [[1,2],[2,2]]
Output: False
Explanation:
The diagonal "[1, 2]" has different elements.

Note:

1. matrix will be a 2D array of integers.
2. matrix will have a number of rows and columns in range [1, 20].
3. matrix[i][j] will be integers in range [0, 99].

class Solution:
    def isToeplitzMatrix(self, matrix):
        """
        :type matrix: List[List[int]]
        :rtype: bool
        """
        if not matrix or not matrix[0]:
            return False
        rowNum = max(0, len(matrix) - 1)
        colNum = max(0, len(matrix[0]) - 1)
        if rowNum is 0 or colNum is 0:
            return True
        for i in range(rowNum):
            for j in range(colNum):
                if matrix[i][j] != matrix[i + 1][j + 1]:
                    return False
        return True
# matrix = [
#     [1, 2, 3, 4],
#     [5, 1, 2, 3],
#     [9, 5, 1, 2]
# ]
# matrix = [
#     [1, 2],
#     [2, 2]
# ]
matrix = [
    [39, 24],
    [24, 39],
    [65, 24]
]
#matrix = [[10], [11], [12]]
s = Solution()
res = s.isToeplitzMatrix(matrix)
print(res)

来自为知笔记(Wiz)