poj 1338

Ugly Numbers

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

Source

New Zealand 1990 Division I,UVA 136

#include<iostream>
#include<cstdio>
#include<cstring>
#include<string>
#include<cmath>
#include<algorithm>
#include<cstdlib>
using namespace std;
int n,dp[1600],i,j,m;
int MIN(int a,int b,int c)
{
a=min(a,b);
return min(a,c);
}
int main()
{
dp[1]=1,i=1,j=1,m=1;
for(int k=2;k<=1500;k++)
{
dp[k]=MIN(dp[i]*2,dp[j]*3,dp[m]*5);
if(dp[k]==dp[i]*2) i++;
if(dp[k]==dp[j]*3) j++;
if(dp[k]==dp[m]*5) m++;
}
while(scanf("%d",&n),n)
printf("%d\n",dp[n]);
return 0;
}