Toeplitz Matrix - LeetCode

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describe

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:

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

The title means that if a matrix has the same elements on the diagonal from upper left to lower right in each direction, then this matrix is 托普利茨矩阵.

Given M x Na matrix of , return if and only if it is a Toeplitz matrix True.

solution

According to the given example, the elements on the diagonal from the upper left to the lower right are the same , such as numbers 1, matrix[0][0]and the positions are Pulitzer matrix. This is very simple, two layers of for loops are done.matrix[1][1]matrix[2][2]2matrix[0][1]matrix[1][2]matrix[2][3]matrix[i][j] == matrix[i+1][j+1]

code show as below:

public boolean isToeplitzMatrix(int[][] matrix) {
    for(int i=0; i<matrix.length-1;i++){
        for(int j=0; j<matrix[i].length-1; j++){
            if(matrix[i][j] != matrix[i+1][j+1]){
                return false;
            }
        }
    }
    return true;
}