LeetCode-in-Java

2133. Check if Every Row and Column Contains All Numbers

Easy

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 true if 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

Solution

import java.util.HashSet;
import java.util.Set;

public class Solution {
    public boolean checkValid(int[][] matrix) {
        int n = matrix.length;
        Set<Integer> set = new HashSet<>();
        for (int[] ints : matrix) {
            for (int anInt : ints) {
                set.add(anInt);
            }
            if (set.size() != n) {
                return false;
            }
            set.clear();
        }
        for (int i = 0; i < matrix[0].length; i++) {
            for (int[] ints : matrix) {
                set.add(ints[i]);
            }
            if (set.size() != n) {
                return false;
            }
            set.clear();
        }
        return true;
    }
}

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