zoj1095 Humble Numbers(DP)-优快云博客

/*
简单DP：每次将求得的值分别乘以2,3,4,7，然后利用插入排序插入到数据序列中
保证数据的递增序，最终到达结束状态。
*/

View Code

 1 #include <iostream>
 2 #include <cstdlib>
 3 #include <stdio.h>
 4 
 5 using namespace std;
 6 
 7 long long data[ 6000 ] = {0,1,2,3,5,7};
 8 
 9 bool bs( int l, int h, long long key )
10 {
11     while ( l <= h ) {
12         int mid = (l+h)/2;
13         if ( data[ mid ] == key )
14             return true;
15         else if ( data[ mid ] > key )
16             h = mid-1;
17         else l = mid+1;
18     }
19     return false;
20 }
21 
22 int main()
23 {
24     int save = 6,move = 2;
25     while ( move < save && save < 6000 ) {
26         for ( int i = 2 ; i <= move ; ++ i ) {
27             data[ save ] = data[ move ]*data[ i ];
28             if ( data[ save ] <= 2000000000 && !bs( 1, save-1, data[ save ] ) ) {
29                 int now = save ++;
30                 while ( data[ now ] < data[ now-1 ] ) {
31                     swap( data[ now ], data[ now-1 ] );
32                     -- now;
33                 }
34             }
35         }
36         ++ move;
37     }
38     int n;
39     while ( scanf("%d",&n) && n ) {
40         cout << "The " << n;
41         if ( n%10 == 1 && n%100 != 11 )
42             cout << "st";
43         else if ( n%10 == 2 && n%100 != 12 )
44             cout << "nd";
45         else if ( n%10 == 3 && n%100 != 13 )
46             cout << "rd";
47         else
48             cout << "th";
49         cout << " humble number is " << data[ n ] << "." << endl;
50     }
51     return 0;
52 }