poj-1338-Ugly Numbers

Ugly Numbers

Time Limit: 1000MS		Memory Limit: 10000K
Total Submissions: 20878		Accepted: 9266

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
#include
#include
#include
#include
#include
#include
#include
using namespace std;
int ugly[1510];
int main()
{
	int n;
	
		memset(ugly,0,sizeof(ugly));
		int a,b,c;
		a=b=c=1;
		ugly[1]=1;
		for(int i=2;i<=1500;i++)
		{
			ugly[i]=min(ugly[a]*2,min(ugly[b]*3,ugly[c]*5));
			if(ugly[i]==ugly[a]*2)  a++;
			if(ugly[i]==ugly[b]*3)  b++;
			if(ugly[i]==ugly[c]*5)  c++;
			
		}
	while(~scanf("%d",&n),n)
	{
		printf("%d\n",ugly[n]);
		
	}
	return 0;
}