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++ (GCC 9.2.1) (judge verdict: Accepted)

#include <iostream>
#include <string>

int main()
{
  int N;
  std::string S;
  std::cin >> N;
  std::cin >> S;
  if (N%2==0) {
    bool flg = true;
    for (int i=0; i<N/2; i++) {
      if (S[i] != S[N/2+i]) {
        flg = false; break;
      }
    }
    if (flg) std::cout << "Yes" << std::endl;
    else std::cout << "No" << std::endl;
  }
  else std::cout << "No" << std::endl;
  return 0;
}