hdu 5211 类似筛法的思想

暴力好像也可以过，不过正解应该是用类似筛法的思想来做。

 1 #include <iostream>
 2 #include <cstring>
 3 #include <cstdio>
 4 using namespace std;
 5 
 6 const int INF = 9999999;
 7 const int N = 10001;
 8 int a[N];
 9 int mp[N];
10 
11 int main()
12 {
13     int n;
14     while ( scanf("%d", &n) != EOF )
15     {
16         memset( mp, -1, sizeof(mp) );
17         int maxn = -1;
18         for ( int i = 1; i <= n; i++ )
19         {
20             scanf("%d", a + i);
21             if ( a[i] > maxn ) maxn = a[i];
22             mp[a[i]] = i;
23         }
24         int ans = 0;
25         for ( int i = 1; i <= n; i++ )
26         {
27             int f = INF;
28             for ( int j = a[i] + a[i]; j <= maxn; j += a[i] )
29             {
30                 if ( mp[j] > i )
31                 {
32                     if ( mp[j] < f ) f = mp[j];
33                 }
34             }
35             if ( f == INF ) f = 0;
36             ans += f;
37         }
38         printf("%d\n", ans);
39     }
40     return 0;
41 }

 

posted @ 2015-04-27 19:00  hxy_has_been_used  阅读(222)  评论(0)  编辑  收藏  举报