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: Wrong Answer)

#include <stdio.h>

int main(void)
{
  int n;
  scanf("%d", &n);
  int index = n / 2;
  char string[n + 1];
  scanf("%s", string);

  if (n == 1)
  {
    printf("No\n");
    return 0;
  }
  for (int i = 0; i < (n / 2) - 1; i++)
  {
    if (string[i] == string[index])
    {
      index++;
    }
    else
    {
      printf("No\n");
      return 0;
    }
  }
  printf("Yes\n");
  return 0;
}