【每日一题Day104】LC2319判断矩阵是否是一个 X 矩阵 | 模拟

判断矩阵是否是一个 X 矩阵【LC2319】

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

1. All the elements in the diagonals of the matrix are non-zero.
2. 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.

感谢力扣 最近的都好简单 家里太忙了 没空学习了

• 思路：如果对角线的元素等于0或者其他元素不等于0，那么返回false

• 实现

  class Solution {
      public boolean checkXMatrix(int[][] grid) {
          int n = grid.length;
          for (int i = 0; i < n; i++){
              for (int j = 0; j < n; j++){
                  if (i == j || i + j == n - 1){
                      if (grid[i][j] == 0) return false;
                  }else{
                      if (grid[i][j] != 0) return false;
                  }
              }
          }
          return true;
      }
  }
  

  • 复杂度
    • 时间复杂度：$O(n^2)$，$n$为矩阵的长度
    • 空间复杂度：$O(1)$