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.

我的解答：

用一个数组存储每次新加入的结果，用一个数组当作primes每个数对应的结果数组的序号。

class Solution {
public:
int nthSuperUglyNumber(int n, vector<int>& primes) {
if(n <= 0) return false;
if(n == 1) return true;
vector<int>mp(primes.size(),0);
vector<int> k;
k.push_back(1);
for(int i = 1; i < n ; i ++)
{
int minn = INT_MAX;
for(int jj = 0; jj < primes.size(); jj++){
if(k[mp[jj]]*primes[jj] < minn)
minn = k[mp[jj]]*primes[jj];
}
k.push_back(minn);
for(int kk = 0; kk < primes.size(); kk++){
if(k[mp[kk]]*primes[kk] == minn){
mp[kk]++;
}
}
}
return k[n-1];
}
};