POJ-1338-Ugly Numbers

#include<iostream>
#include<queue>
#include<vector>
#include<cstdio>
#define MAX 1501
using namespace std;
int main()
{
long long result[MAX];
priority_queue<pair<long long,int>, vector<pair<long long,int> >,greater< pair<long long,int> > > Q;
Q.push(make_pair(1,2));
for(int i=0;i<MAX;i++)
{
pair<long long ,int> node=Q.top();
Q.pop();
switch(node.second)
{
case 2:Q.push(make_pair(node.first*2,2));
case 3:Q.push(make_pair(node.first*3,3));
case 5:Q.push(make_pair(node.first*5,5));
}
result[i]=node.first;
}
int n;
while(scanf("%d",&n)&&n)
{
printf("%d\n",result[n-1]);
}
return 0;
}