hdu 1058 Humble Numbers

 1 #include<cstdio>
 2 #include<cstring>
 3 #include<cmath>
 4 #include<algorithm>
 5 #define For(i,s,t)    for(int i=s; i<=t; ++i)
 6 using namespace std;
 7 typedef long long LL;
 8 const int inf= 2000000000;
 9 
10 LL value[6002];
11 LL pw2[32]={1}, pw3[21]={1}, pw5[15]={1}, pw7[13]={1};
12 
13 int init(){
14     For(i,1,31)   pw2[i]= pw2[i-1]<<1;
15     For(i,1,20)      pw3[i]= pw3[i-1]*3;
16     For(i,1,14)      pw5[i]= pw5[i-1]*5;
17     For(i,1,12)      pw7[i]= pw7[i-1]*7;
18     int num= 0;
19     LL tmp1,tmp2,tmp3;
20     for(int i=0; i<=31; ++i)
21         for(int j=0; j<=20; ++j){
22             if((tmp1= pw2[i]*pw3[j])> inf)    break;
23             for(int k=0; k<=14; ++k){
24                 if((tmp2= tmp1*pw5[k])> inf)    break;
25                 for(int p=0; p<=12; ++p){
26                     if((tmp3= tmp2*pw7[p])> inf)    break;
27                     value[++num]= tmp3;
28                 }
29             }
30         }
31     sort(value+1,value+num+1);
32     return num;
33 }
34 
35 char s[4][5]= {"th","st","nd","rd"};
36 
37 int main(){
38     int num= init(),n;
39     while(~scanf("%d",&n),n)
40         printf("The %d%s humble number is %lld.\n",n, n%10<=3 &&(n%100<11||n%100>13)? s[n%10]:"th", value[n]);
41     return 0;
42 }