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: TrueExplanation: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: FalseExplanation:The diagonal "[1, 2]" has different elements.

class Solution {    public boolean isToeplitzMatrix(int[][] matrix) {        if (matrix == null)            return false;        for (int i=0; i