poj----1338

Description

Ugly numbers are numbers whose only prime factors are 2, 3 or 5. The sequence 
1, 2, 3, 4, 5, 6, 8, 9, 10, 12, ... 
shows the first 10 ugly numbers. By convention, 1 is included. 
Given the integer n,write a program to find and print the n'th ugly number. 

Input

Each line of the input contains a postisive integer n (n <= 1500).Input is terminated by a line with n=0.

Output

For each line, output the n’th ugly number .:Don’t deal with the line with n=0.

Sample Input

1
2
9
0

Sample Output

1
2
10

#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<math.h>
#include<iostream>
#include<algorithm>

using namespace std;

#define N 1509
int f[N];
int main()
{
    int a2,a3,a5,i,tmp,n;
    a2=a3=a5=1;
    f[1]=1;
    for(i=2; i<N; i++)
    {
        tmp=min(f[a2]*2,f[a3]*3);
        tmp=min(tmp,f[a5]*5);
        f[i]=tmp;
        if(tmp==f[a2]*2)
            ++a2;
        if(tmp==f[a3]*3)
            ++a3;
        if(tmp==f[a5]*5)
            ++a5;

    }
    while(scanf("%d",&n)!=EOF)
    {
        if(n==0)
            break;

        printf("%d\n", f[n]);
    }
    return 0;
}