AC题解，递归普及组有两道一样的题

#include<bits/stdc++.h>
using namespace std;
int main(){
long long i,n,s;
string a,s1,s2,cl;
cin>>a;
n=a.size();
while(s1==s2){
s=s1.size();
s1=s2=cl;
for(i=0;i<n/2;i++)s1+=a[i];
for(i=n-1;i>=n/2;i--)s2+=a[i];
n/=2;
}
if(s){
cout<<s;
}
else{
cout<<a.size();
}
}