Check if Every Row and Column Contains All Numbers.java

// Runtime: 56 ms (Top 50.77%) | Memory: 92.4 MB (Top 46.57%)
class Solution {
    public boolean checkValid(int[][] matrix) {
        int n = matrix.length;
        int num = (n*(n+1))/2; // SUM of n number 1 to n;

        for(int i=0; i<n; i++)
        {
            HashSet<Integer> hs = new HashSet<Integer>();
              HashSet<Integer> hs1 = new HashSet<Integer>();

            int m = num; int k = num;

            for(int j = 0; j<n; j++)
            {
                hs.add(matrix[i][j]);
                  hs1.add(matrix[j][i]);
                m -= matrix[i][j];
                k -= matrix[j][i];
            }

            if(m != 0 || k != 0 || hs.size() != n || hs.size() != n)
            {
                return false;
            }
        }
        return true;
    }
}