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()
{
	int n,i;
	char c[150];
	scanf("%d",&n);
	getchar();
	gets(c);
	if(n%2!=0)printf("NO\n");
	  else {
	  	for(i=n/2;i<n;i++)
	  	if(c[i]!=c[i-n/2])
	  	 {
	  	 	
		  printf("NO\n");
		  return 0;
		   }
		   printf("YES\n");
	  	
	  }
}