Julka

#include <bits/stdc++.h>
using namespace std;
string s;
int wazne, P[1000007], n, k;
int main()
{
    cin >> n >> s;
    for ( int i=1; i<n ; i++)
    {
        while (k>0 and s[i]!=s[k])
        {
            k=P[k-1];
        }
        if( s[i]==s[k])
        {
            k=k+1;
        }
        P[i]=k;
    }
    wazne=P[n-1];
    for ( int i=0; i<n-1-P[n-1]; i++)
    {
    P[i]=P[i+P[n-1]];
    }
    k=0;
    for ( int i=1; i<n-2*P[n-1] ; i++)
    {
        while (k>0 and s[i]!=s[k])
        {
            k=P[k-1];
        }
        if( s[i]==s[k])
        {
            k=k+1;
        }
        P[i]=k;
    }
    cout<<P[n-2*P[n-1]-1]+wazne;
}