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 5.4.1) (judge verdict: Wrong Answer)

#include <stdio.h>

int main(void){
  int n;
  int frag=0;
  char s[101];
  scanf("%d",&n);
  for(int i=0;i<n;i++){
    scanf("%c",&s[i]);
  }
  for(int i=0;i<(int)(n/2);i++){
    if(s[i]!=s[i+(int)(n/2)]){

      frag=1;

      break;

    }
  }
  if(frag==0){
    printf("Yes\n");
  }else{
    printf("No\n");
  }
  return 0;
}