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: Accepted)

#include <stdio.h>
int main(void){
	char s[101];
	int a;
	scanf("%d%s",&a,s);
	int i,len=0,c=0;
	for(i=0;s[i]!='\0';i++) len++;
	if(len%2==1) c=1;
	else for(i=len/2;i<len;i++) if(s[i]!=s[i-len/2]) c=1;
	printf(c==0?"Yes":"No");
	return 0;
}