UVA – 455 – Periodic Strings

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;

vector<ll>pi;
void preFunc(string s)
{
    ll len=(ll)s.size();
    pi.resize(len+5);
    pi[0]=0;
    for(ll i=1;i<len;i++){
        ll j=pi[i-1];
        while((j>0)&&(s[i]!=s[j]))j=pi[j-1];
        if(s[i]==s[j])j++;
        pi[i]=j;
    }
}

int main()
{
    ll t;
    cin>>t;
    ll ck=0;
    while(t--){
        string s;
        cin>>s;
        ll len=s.size();
        if(ck==0)ck=1;
        else cout<<"\n";
        preFunc(s);
        ll ans=len;
        ll tmp=len-pi[len-1];
        if(len%tmp==0)ans=tmp;
        cout<<ans<<"\n";
    }
    return 0;
}
Code language: PHP (php)