Cod sursa(job #590747)
#include<stdio.h>
#include<string.h>
#define N 10000000
char s[N],w[N],c;
long n,k,p[N],i,j,q,r[N],max,l,d,v[N],u,t;
int main()
{FILE *f=fopen("prefix.in","r");
FILE *g=fopen("prefix.out","w");
fscanf(f,"%ld\n",t);
while(t--)
{fgets(s,N,f);
n=strlen(s);
k=q=l=p[1]=r[1]=u=max=0;
for(i=2;i<n;i++)
{while(k>0&&s[k+1]!=s[i])
k=p[k];
if(s[k+1]==s[i])
k++;
p[i]=k;
if(p[i]>max)
{max=p[i];
j=i-max;}}
for(i=0;i<j;i++)
w[i]=s[i];
for(i=2;i<j;i++)
{while(q>0&&w[q+1]!=w[i])
q=r[q];
if(w[q+1]==w[i])
q++;
r[i]=q;}
for(i=1;i<n;i++)
{while(l>0&&w[l+1]!=s[i])
l=r[l];
if(w[l+1]==s[i])
l++;
if(l==j-1&&w[0]==s[i-l])
v[++u]=i-j+1;}
d=v[1]+j;
for(i=2;i<=u;i++)
if(v[i]-v[i-1]==j)
d=v[i]+j;
else
break;
fprintf(g,"%ld\n",d);}
fclose(f);
fclose(g);
return 0;}