Super Ugly Number Solutions in C++

// Source : https://leetcode.com/problems/super-ugly-number/
// Author : Hao Chen
// Date   : 2017-01-02



// As the solution we have for the ugly number II problem
//
//    int nthUglyNumber(int n) {
//
//        int i=0, j=0, k=0;
//        vector<int> ugly(1,1);
//
//        while(ugly.size() < n){
//            int next = min(ugly[i]*2, ugly[j]*3, ugly[k]*5);
//            if (next == ugly[i]*2) i++;
//            if (next == ugly[j]*3) j++;
//            if (next == ugly[k]*5) k++;
//            ugly.push_back(next);
//        }
//        return ugly.back();
//    }
//
// The logic of solution is exacly same for both., except that instead of 3 numbers you have k numbers to consider. 
//
// 
//
class Solution {
  
public:
    int nthSuperUglyNumber(int n, vector<int>& primes) {
        vector<int> ugly(1, 1);
        int len = primes.size();
        vector<int> pos(len, 0);
        
        while( ugly.size() < n ) {
            int next = INT_MAX;
            for(int i=0; i<len; i++) {
                next = min(next, ugly[pos[i]] * primes[i]);
            }
            for(int i=0; i<len; i++) {
                if (next == ugly[pos[i]] * primes[i]) {
                    pos[i]++;
                }
            }
            ugly.push_back(next);
        }
        return ugly.back();
    }
    

};