Check if Matrix Is X-Matrix — LeetCode 2319 Python Solution

The problem

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.

Example

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.

Python solution

class Solution:
    def checkXMatrix(self, grid: List[List[int]]) -> bool:
        for i, row in enumerate(grid):
            for j, v in enumerate(row):
                if i == j or i + j == len(grid) - 1:
                    if v == 0:
                        return False
                elif v:
                    return False
        return True

Complexity

Pattern: Matrix and Grid

Treat a 2-D grid as a graph whose neighbours are the four adjacent cells. LeetCode 2319. Check if Matrix Is X-Matrix is filed here on both counts: the reference solution below belongs to the algorithm family this hub collects, and LeetCode tags it Matrix.

The matrix and grid guide has the Python template for the pattern and the 216 LeetCode problems that use it.

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