313. Super Ugly Number

题目：

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.

解题思路：

思路类似ugly number那一题

class Solution {
public:
int nthSuperUglyNumber(int n, vector<int>& primes) {
vector<int> ugly(n,INT_MAX), index(primes.size(),0);
ugly[0] = 1;
for(int i=1;i<n;i++){
for(int j=0;j<primes.size();j++)ugly[i] = min(ugly[i],ugly[index[j]]*primes[j]);
for(int k=0;k<primes.size();k++)index[k] += (ugly[index[k]]*primes[k]==ugly[i]);
}
return ugly[n-1];

}
};