Leetcode: Super Ugly Number

Write a program to find the nth super ugly number.

Super ugly numbers are positive numbers whose all prime factors are in the given prime list primes of size k. For example, [1, 2, 4, 7, 8, 13, 14, 16, 19, 26, 28, 32] is the sequence of the first 12 super ugly numbers given primes = [2, 7, 13, 19] of size 4.

Note:
(1) 1 is a super ugly number for any given primes.
(2) The given numbers in primes are in ascending order.
(3) 0 < k ≤ 100, 0 < n ≤ 106, 0 < primes[i] < 1000.

 1 public class Solution {
 2     public int nthSuperUglyNumber(int n, int[] primes) {
 3         int[] uglys = new int[n];
 4         uglys[0] = 1;
 5         int[] pointers = new int[primes.length];
 6         
 7         for (int i=1; i<=n-1; i++) {
 8             int min=Integer.MAX_VALUE;
 9             ArrayList<Integer> minPm = new ArrayList<Integer>(); // initialization
10             for (int j=0; j<primes.length; j++) {
11                 if (uglys[pointers[j]] * primes[j] <= min) {
12                     if (uglys[pointers[j]] * primes[j] < min) {
13                         min = uglys[pointers[j]] * primes[j];
14                         minPm = new ArrayList<Integer>();
15                     }
16                     minPm.add(j);
17                 }
18             }
19             for (int k=0; k<minPm.size(); k++) {
20                 pointers[minPm.get(k)]++;
21             }
22             uglys[i] = min;
23         }
24         return uglys[n-1];
25     }
26 }