[LeetCode&Python] Problem 766. Toeplitz Matrix

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:
In the above grid, the diagonals are:
"[9]", "[5, 5]", "[1, 1, 1]", "[2, 2, 2]", "[3, 3]", "[4]".
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
        """
        Flag=True
        m=len(matrix)
        n=len(matrix[0])
        
        for i in range(m):
            row=i
            column=0
            stan=matrix[i][0]
            while row<m and column<n:
                if matrix[row][column]!=stan:
                    Flag=False
                    break
                row+=1
                column+=1
        
        if Flag:
            for j in range(1,n):
                column=j
                row=0
                stan=matrix[0][j]
                while column<n and row<m:
                    if matrix[row][column]!=stan:
                        Flag=False
                        break
                    row+=1
                    column+=1
        
        return Flag