Problem:
Score : 200 points

Problem Statement

Given are a positive integer N and a string S of length N consisting of lowercase English letters.

Determine whether the string is a concatenation of two copies of some string.
That is, determine whether there is a string T such that S = T + T.

Constraints

1 \leq N \leq 100

S consists of lowercase English letters.

|S| = N

Input

Input is given from Standard Input in the following format:

N
S

Output

If S is a concatenation of two copies of some string, print Yes; otherwise, print No.

Sample Input 1

6
abcabc

Sample Output 1

Yes

Let T = abc, and S = T + T.

Sample Input 2

6
abcadc

Sample Output 2

No

Sample Input 3

1
z

Sample Output 3

No

Solution in C++14 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <bits/stdc++.h>
#define ll long long
#define ALL(x) x.begin(),x.end()
#define MOD (1000000000+7)
using namespace std;
#define PI 3.14159265359
#define tMOD 998244353
#define mkpr(x,y) make_pair(x,y)



int main(){
ll N;string S;
cin>>N>>S;

if(N%2==1){
  cout<<"No"<<endl;
}
ll ff=1;
for(ll i=0;i<N/2;i++){
  if(S[i]!=S[N-1-i]){
    ff=0;
  }
}

if(ff==0){
  cout<<"No"<<endl;
}
else{
  cout<<"Yes"<<endl;
}




}