HDU 1358 (所有前缀中的周期串) Period

 1 #include <cstdio>
 2 #include <cstring>
 3 
 4 const int maxn = 1000000 + 10;
 5 char p[maxn];
 6 int n, next[maxn];
 7 
 8 void get_next()
 9 {
10     int k = -1, j = 0;
11     next[0] = -1;
12     while(j < n)
13     {
14         if(k == -1 || p[k] == p[j])
15         {
16             k++;
17             j++;
18             next[j] = k;
19         }
20         else k = next[k];
21     }
22 }
23 
24 int main(void)
25 {
26     //freopen("1358in.txt", "r", stdin);
27     int kase = 0;
28     while(scanf("%d", &n) == 1 && n)
29     {
30         memset(next, 0, sizeof(next));
31         scanf("%s", p);
32         getchar();
33         get_next();
34         
35         printf("Test case #%d\n", ++kase);
36         for(int i = 2; i <= n; ++i)
37         {
38             if(next[i] == 0) continue;
39             int cir = i - next[i];
40             if(i % cir == 0)
41                 printf("%d %d\n", i, i / cir);
42         }
43         puts("");
44     }
45 
46     return 0;
47 }