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: Accepted)

#include<iostream>
using namespace std;

int main(){
  int N;
  string S1,S2;
  cin >> N;
  if(N%2==0){
    for(int i=1;i<=N/2;i++){
      char c;
      cin >> c;
      S1 += c;
    }
    for(int i=1;i<=N/2;i++){
      char c;
      cin >> c;
      S2 += c;
    }
    if(S1==S2){
      cout << "Yes" << endl;
    }
    else{
      cout << "No" << endl;
    }
  }
  else{
    cout << "No" << endl;
  }
}