poj 1338 Ugly Numbers

#include <iostream>
using namespace std;
int factor[3]={2,3,5},prime[1510]={1};
int start[3];
int main()
{
    int i,j,min,n;
    for(i=1;i<1510;i++)
    {
        min=2147483647;
        for(j=0;j<3;j++)
            if(prime[start[j]]*factor[j]<min)
                min=prime[start[j]]*factor[j];
        prime[i]=min;
        for(j=0;j<3;j++)
            if(prime[start[j]]*factor[j]==min)
                start[j]++;
    }
    while(scanf("%d",&n)&&n)
    {
        printf("%d\n",prime[n-1]);
    }
    return 0;
}