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

Now given anM x Nmatrix, return True if and only if the matrix isToeplitz.

Note:

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

按照要求，一个一个对角线地检查就可以了

class Solution {
    public boolean isToeplitzMatrix(int[][] matrix) {
        int m = matrix.length;
        int n = matrix[0].length;

        if(m == 1 || n == 1)
            return true;

        for(int k = 0; k < n; k++) {
            int i = 0;
            int j = k;

            int num = matrix[i][j];
            while(i < m && j < n) {
                if(matrix[i][j] != num)
                    return false;
                i++;
                j++;
            }
        }

        for(int k = 0; k < m; k++) {
            int i = k;
            int j = 0;

            int num = matrix[i][j];
            while(i < m && j < n) {
                if(matrix[i][j] != num)
                    return false;
                i++;
                j++;
            }
        }

        return true;
    }
}