poj 1338 Ugly Numbers

原题链接：http://poj.org/problem?id=1338

优先队列的应用，如下：

 #include<cstdio>
 #include<cstdlib>
 #include<queue>
 #include<functional>
 #include<iostream>
 #include<algorithm>
 using namespace std;
 typedef long long ll;
 const int Max_N = ;
 ll ans[Max_N];
 void init(){
     int arr[] = { , ,  };
     priority_queue<ll, vector<ll>, greater<ll> > que;
     que.push();
     for (int i = ; i <= ;){
         ll t = que.top();
         que.pop(), ans[i] = t;
         if (ans[i] == ans[i - ]){
             continue;
         } else {
             i++;
         }
         for (int j = ; j < ; j++) que.push((ll)(t * arr[j]));
     }
 }
 int main(){
     init();
     int n;
     while (~scanf("%d", &n) && n) printf("%lld\n", ans[n]);
     return ;
 }