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.

Example:

Input: n = 12, primes = [2,7,13,19]
Output: 32 
Explanation: [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 is a super ugly number for any given primes.

  • The given numbers in primes are in ascending order.

  • 0 < k ≤ 100, 0 < n ≤ 106, 0 < primes[i] < 1000.

  • The nth super ugly number is guaranteed to fit in a 32-bit signed integer.

class Solution {
    public int nthSuperUglyNumber(int n, int[] primes) {
        int indices[] = new int[primes.length];
        int dp[] = new int[n];
        dp[0] = 1;
        for (int i = 1; i < n; i++) {
            int min = Integer.MAX_VALUE;
            for (int j = 0; j < primes.length; j++)
                min = Math.min(min, primes[j] * dp[indices[j]]);
            for (int j = 0; j < primes.length; j++) {
                if (min == primes[j] * dp[indices[j]])
                    indices[j]++;
            }
            dp[i] = min;
        }
        return dp[n - 1];
    }
}

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