An n x n matrix is valid if every row and every column contains all the integers from 1 to n (inclusive).
Given an n x n integer matrix matrix, return trueif the matrix is valid. Otherwise, return false.
Example 1:
Input: matrix = [[1,2,3],[3,1,2],[2,3,1]]
Output: true
Explanation: In this case, n = 3, and every row and column contains the numbers 1, 2, and 3.
Hence, we return true.
Example 2:
Input: matrix = [[1,1,1],[1,2,3],[1,2,3]]
Output: false
Explanation: In this case, n = 3, but the first row and the first column do not contain the numbers 2 or 3.
Hence, we return false.
Constraints:
n == matrix.length == matrix[i].length
1 <= n <= 100
1 <= matrix[i][j] <= n
Solutions
Solution 1: Hash Table
Traverse each row and column of the matrix, using a hash table to record whether each number has appeared. If any number appears more than once in a row or column, return false; otherwise, return true
The time complexity is $O(n^2)$, and the space complexity is $O(n)$. Here, $n$ is the size of the matrix.