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,d=0,i,j;
	char s[101],t[51];
	scanf("%d",&n);
	scanf("%s",s);

	for(i=0;i<n/2;i++){
		t[i]=s[i];
	}
	for(j=0;j<n;j++){
		if(s[i++] != t[j]){
			d=1;
			break;
		}
	}
	if(d==1 || n%2==1){
		printf("No\n");
	}else{
		printf("Yes\n");
	}
}