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>
#include <string.h>
#include <stdbool.h>
int main(){
	char str[101]={};
	int n;
	scanf("%d", &n);
	scanf("%s", str);
	bool exist=true;
	if(n%2==1){
		exist=false;
	}else{
		for (int i = 0; i < n / 2; i++) {
			if(str[i]!=str[n/2+i]){
				exist=false;
				break;
			}
		}
	}
	if(exist)
		printf("Yes\n");
	else
		printf("No\n");
	return 0;
}