ugly number

public int (int num, int div) {
    while (num % div == 0)
        num /= div;
    return num;
}

public boolean helper(int num) {
    num = divider(num, 2);
    num = divider(num, 3);
    num = divider(num, 5);
    if (num == 1)
        return true;
    return false;
}

public boolean isUgly(int num) {
    if (num == 1)
        return true;
    if (num <= 0)
        return false;
    
    for (int i = 2; i <= 5; ++i) {
        while (num % i == 0)
            num /= i;
    }
    return num == 1;
}

public int nthUglyNumber(int n) {
    PriorityQueue<Long> q = new PriorityQueue<>();
    q.offer(1l);
    long val = 0;
    HashSet<Long> visited = new HashSet<>();
    for (int i = 1; i <= n; ++i) {
        val = q.poll();
        if (visited.contains(val * 2) == false) {
            visited.add(val * 2);
            q.offer(val * 2);
        }
        if (visited.contains(val * 3) == false) {
            visited.add(val * 3);
            q.offer(val * 3);
        }
        if (visited.contains(val * 5) == false) {
            visited.add(val * 5);
            q.offer(val * 5);
        }
    }
    return (int)val;
}