poj 1961 period

 1 #include <cstdio>
 2 #include <iostream>
 3 #include <string.h>
 4 #include <string> 
 5 #include <map>
 6 #include <queue>
 7 #include <deque>
 8 #include <vector>
 9 #include <set>
10 #include <algorithm>
11 #include <math.h>
12 #include <cmath>
13 #include <stack>
14 #include <iomanip>
15 #define mem0(a) memset(a,0,sizeof(a))
16 #define meminf(a) memset(a,0x3f,sizeof(a))
17 #define ll long long
18 using namespace std;
19 int nex[1000005];
20 int getn(int n,char c[])
21 {
22     int i=0,j=-1;
23     nex[0]=-1;
24     while(i<n)
25     {
26         if(c[i]==c[j]||j==-1)
27         {
28             i++;j++;nex[i]=j;
29         }
30         else j=nex[j];
31     }
32 }
33 int main()
34 {
35     int n,k=1;
36     char c[1000005];
37     int count=1;
38     while(scanf("%d",&n)&&n)
39     {
40        scanf("%s",c);
41        getn(n,c);
42        printf("Test case #%d\n",count++);
43               for(int i=0;i<=n;++i) cout<<"nec[i]="<<nex[i]<<endl;
44        for(int i=1;i<=n;++i)
45        {
46            int temp=i-nex[i];
47            if(i%temp==0&&i/temp>1) printf("%d %d\n",i,i/temp);
48        }
49        printf("\n");
50     }
51     return 0;
52 }