丑数（UVa136）

　　

　　题目具体描述见：https://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&category=835&page=show_problem&problem=72

C++11代码如下：

 #include<iostream>
 #include<vector>
 #include<set>
 #include<queue>
 using namespace std;

 typedef long long LL;
 const int coeff[] = { ,, };
 int main() {
     priority_queue<LL, vector<LL>, greater<LL> >pq;
     set<LL>s;
     pq.push();
     s.insert();
     for (int i = ;; i++) {
         LL x = pq.top(); pq.pop();
         if (i == ) {
             cout << "The 1500'th ugly number is " << x << '.' << endl;
             break;
         }
         for (int j = ; j < ; j++) {
             LL x2 = x * coeff[j];
             if (!s.count(x2)) {
                 s.insert(x2);
                 pq.push(x2);
             }
         }
     }
     return ;
 }