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