2319.go

// Source: https://leetcode.com/problems/check-if-matrix-is-x-matrix
// Title: Check if Matrix Is X-Matrix
// Difficulty: Easy
// Author: Mu Yang <http://muyang.pro>

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// 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:
//
//   https://assets.leetcode.com/uploads/2022/05/03/ex1.jpg
//
//   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:
//
//   https://assets.leetcode.com/uploads/2022/05/03/ex2.jpg
//
//   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] <= 10^5
//
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

package main

func checkXMatrix(grid [][]int) bool {
	n := len(grid)

	for i, row := range grid {
		for j, val := range row {
			isDiag := (i == j || i+j == n-1)
			if (isDiag && val == 0) || (!isDiag && val != 0) {
				return false
			}
		}
	}

	return true
}