Check if Every Row and Column Contains All Numbers

给一个矩阵, 判断row和col是不是都是有[1,n]n个不同的数字组成.

class Solution {
    public boolean checkValid(int[][] matrix) {
        int n = matrix.length;
        for(int i = 0; i < n; i++) { // row
            Set<Integer> set = new HashSet<>();
            for(int j = 0; j < n; j++) {
                if(1 <= matrix[i][j] && matrix[i][j] <= n)
                    set.add(matrix[i][j]);
            }
            if(set.size() != n)
                return false;
        }
        for(int i = 0; i < n; i++) { // col
            Set<Integer> set = new HashSet<>();
            for(int j = 0; j < n; j++) {
                if(1 <= matrix[j][i] && matrix[j][i] <= n)
                    set.add(matrix[j][i]);
            }
            if(set.size() != n)
                return false;
        }
        return true;
    }
}