README.md

2319. Check if Matrix Is X-Matrix

A square matrix is said to be an X-Matrix if both of the following conditions hold:

• All the elements in the diagonals of the matrix are non-zero.
• All other elements are 0.

Given a 2D integer array grid of size n x n representing a square matrix, return true if grid is an X-Matrix. Otherwise, return false.

Example 1:

Input: grid = [[2,0,0,1],[0,3,1,0],[0,5,2,0],[4,0,0,2]]
Output: true
Explanation: Refer to the diagram above.
An X-Matrix should have the green elements (diagonals) be non-zero and the red elements be 0.
Thus, grid is an X-Matrix.

Example 2:

Input: grid = [[5,7,0],[0,3,1],[0,5,0]]
Output: false
Explanation: Refer to the diagram above.
An X-Matrix should have the green elements (diagonals) be non-zero and the red elements be 0.
Thus, grid is not an X-Matrix.

Constraints:

• n == grid.length == grid[i].length
• 3 <= n <= 100
• 0 <= grid[i][j] <= 105

Solutions (Python)

1. Solution

class Solution:
    def checkXMatrix(self, grid: List[List[int]]) -> bool:
        for x in range(len(grid)):
            for y in range(len(grid)):
                if (x == y or x == len(grid) - 1 - y) ^ (grid[x][y] != 0):
                    return False

        return True