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>

char S[10010];
int N;
int ans = 0;

int main()
{
	scanf("%d", &N);
	scanf("%s", S);


	if (N % 2 != 0) {
		ans = ans++;
	}else {
		for (int i = 0; i < N / 2; i++) {
			if (S[i] != S[i + N / 2]){
				ans = ans++;
			}
		}
	}

	if (ans != 0) {
		printf("No");
	}
	else {
		printf("Yes");
	}

	return 0;
}