Is Check if Matrix Is X-Matrix easy or hard?

Check if Matrix Is X-Matrix is classified as an Easy problem. It focuses on basic matrix traversal and index conditions rather than complex algorithms. The main challenge is correctly identifying the two diagonals and applying the validation rules.

Check if Matrix Is X-Matrix Python/Java solution

In both Python and Java, the implementation uses nested loops over the matrix indices. The program checks diagonal conditions with i == j or i + j == n - 1 and validates whether the value should be non-zero or zero accordingly. The logic is identical across languages and runs in O(n^2) time.

How to solve Check if Matrix Is X-Matrix in O(n^2)?

Iterate through the matrix using two nested loops. For each cell (i, j), check if it lies on a diagonal using the conditions i == j or i + j == n - 1. If it is a diagonal cell, ensure the value is non-zero; otherwise ensure the value is zero. If any condition fails, return false; otherwise return true after the full traversal.

What is the best approach for Check if Matrix Is X-Matrix?

The most efficient approach is a single-pass matrix traversal. Iterate through every cell and check whether it belongs to the primary diagonal (i == j) or secondary diagonal (i + j == n - 1). Diagonal cells must be non-zero, and all other cells must be zero. This solution runs in O(n^2) time with O(1) extra space.

Is Check if Matrix Is X-Matrix asked at Google/Amazon/Meta?

Matrix validation and traversal problems appear frequently in coding interviews at companies like Amazon, Google, and Meta. While this exact problem may vary, recognizing diagonal conditions and performing structured matrix checks is a common interview pattern.

What data structure is used in Check if Matrix Is X-Matrix?

The problem uses a two-dimensional array (matrix). The algorithm relies on index arithmetic to identify the primary and secondary diagonals rather than additional data structures.

What is the time complexity of Check if Matrix Is X-Matrix?

The time complexity is O(n^2) because every element in the n x n matrix must be checked at least once. Each validation involves constant-time comparisons to determine whether the cell lies on a diagonal. The space complexity remains O(1) since no extra data structures are used.

Description Hints 2 Solution Video 5:30

2319. Check if Matrix Is X-Matrix

Easy67.2% acceptance2 companies

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: