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.

用一个arraylist来存同时赢得竞标的primes, 然后这些primes对应的pointer都要往后移一位

public class Solution {
    public int nthSuperUglyNumber(int n, int[] primes) {
        int[] uglys = new int[n];
        uglys[0] = 1;
        int[] pointers = new int[primes.length];
        
        for (int i=1; i<=n-1; i++) {
            int min=Integer.MAX_VALUE;
            ArrayList<Integer> minPm = new ArrayList<Integer>(); // initialization
            for (int j=0; j<primes.length; j++) {
                if (uglys[pointers[j]] * primes[j] <= min) {
                    if (uglys[pointers[j]] * primes[j] < min) {
                        min = uglys[pointers[j]] * primes[j];
                        minPm = new ArrayList<Integer>();
                    }
                    minPm.add(j);
                }
            }
            for (int k=0; k<minPm.size(); k++) {
                pointers[minPm.get(k)]++;
            }
            uglys[i] = min;
        }
        return uglys[n-1];
    }
}