public class Solution {
    public boolean isPerfectSquare(int n) {
        if(n == 0) return true; 
        System.out.println("n = " + n);
        double k = Math.pow(n, 0.5);
        System.out.println("k = " + k);
        if(k % 1 == 0  && k * k == n) return true; 
        return false;
    }
}