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>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define intput(i) cout << i << endl
#define ll long long
#define stringput(s) cout << (string)(s) << endl

int main(){
  int N;
  cin >> N;
  string S;
  cin >> S;
  if(N%2 == 0){
    rep(i,N/2-1){
      if(S[i] == S[i+N/2]){
        continue;
      }
      else {
        cout << "No" << endl;
        return 0;
      }
    }
  }
  else{
      cout << "No" << endl;
      return 0;
  }
    cout << "Yes" << endl;
    
}