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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
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#include<iostream>
#include<cstdio>
#include<cstring>
#include<cmath>
#include<string>
#include<algorithm>
#include<cstdlib>
#include<set>
#include<queue>
#include<stack>
#include<vector>
#include<map>
#define N 1510
#define Mod 10000007
#define lson l,mid,idx<<1
#define rson mid+1,r,idx<<1|1
#define lc idx<<1
#define rc idx<<1|1
const double EPS = 1e-11;
const double PI = acos ( -1.0 );
const double E = 2.718281828;
typedef long long ll;
const int INF = 1000010;
using namespace std;
int n;
int num[1515];
void init() {
int n2=1,n3=1,n5=1;
num[1]=1;
for(int i=2; i<=N; i++) {
num[i]=min(num[n2]*2,min(num[n3]*3,num[n5]*5));
if(num[i]==num[n2]*2)n2++;
if(num[i]==num[n3]*3)n3++;
if(num[i]==num[n5]*5)n5++;
}
}
int main() {
init();
while(~scanf("%d",&n)&&n)
printf("%d\n",num[n]);
}
原文地址：http://blog.csdn.net/acm_baihuzi/article/details/44064695
