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>
#include<string.h>
int main()
{
   int n,k,i,c;
   scanf("%d",&n);
   if(n%2==0){
   char a[n];
   for(i=0;i<n;i++)
   scanf("%c",&a[i]);
   for(k=0;k<n/2;k++)
  {if(a[k]==a[k+i/2])
    c=0;
   else
    c=1;}
    if(c==0)
    printf("Yes");
    else
     printf("No");
   }
   else
    printf("No");
   return 0;
}