【KMP】Period

 1 #include<iostream>
 2 #include<stdio.h>
 3 using namespace std;
 4 
 5 char s[1000001];
 6 int Next[1000001];
 7 
 8 void getNext(int n){
 9     int i=0,j=-1;
10     Next[0]=-1;
11     while(i<n){
12         if(j==-1||s[i]==s[j]){
13             i++;j++;
14             Next[i]=j;
15         }
16         else j=Next[j];
17     }
18 }
19 
20 int main()
21 {
22     int n,k,t=1,p;
23     //freopen("pe.txt","r",stdin);
24     while(cin>>n&&n>1&&n<1000001){
25         cin>>s;
26         getNext(n);
27         cout<<"Test case #"<<t++<<endl;
28         for(k=2;k<=n;k++){
29             p=k-Next[k];        //循环节的长度
30             if(k%p==0&&k/p>1)
31                 cout<<k<<‘ ‘<<k/p<<endl;    //若字符串由循环节构成，第k个字母前完整循环节数
32         }
33         cout<<endl;
34     }
35     return 0;
36 }