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(void){
	int n;
	int f=0;
	char s[256];
	scanf("%d",&n);
	scanf("%s",s);
	char s2[256];
	char s3[256];
	if(n%2==0){
		for(int i=0; i<n/2; i++){
			s2[i]=s[i];
			s3[i]=s[i];
		}
		strcat(s3,s2);
		if(strcmp(s,s3)==0){
			f=1;
		}
		if(f==1){
			printf("Yes\n");
		}
		else{
			printf("No\n");
		}
	}
	else{
		printf("No\n");
	}
	return 0;
}