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 <stdio.h>
int main() {
  int N;
  scanf("%d", &N);
  char S[N + 1];
  scanf("%s", S);
  int length = N / 2;
  int ans = 0;
  if (N % 2 != 0) {
    ++ans;
  }
  for (int i = 0; i < length; ++i) {
    if (S[i] != S[i+length]) {
      ++ans;
      break;
    }
  }
  if (ans == 0) {
    printf("Yes");
  } else {
    printf("No");
  }
  return 0;
}