UVa 136 Ugly Numbers

#include<iostream>#include<cstdio>#include<string>#include<map>#include<algorithm>#include<vector>#include<queue>#include<set>#include<cstring>#include<stack>using namespace std;const int arr[]={2,3,5};typedef long long  LL;int main(){priority_queue<LL,vector<LL>,greater<LL> > pq;int i,j;set<LL> S;S.insert(1);pq.push(1);for(i=1;;i++){LL t=pq.top();pq.pop();if(i==1500){cout<<"The 1500'th ugly number is "<<t<<"."<<endl;break;}for(j=0;j<3;j++){LL num=t*arr[j];if(!S.count(num)){pq.push(num);S.insert(num);}}}return 0;}