【LeetCode】 313. 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.

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

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