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++14 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include<stdio.h>
#include<string.h>
#include<algorithm>
#include<vector>
typedef long long ll;
using namespace std;

int main()
{
	int N;
	char S[110] = { 0, };
	scanf("%d%s", &N, S);
	if (N % 2) {
		int i = 0;
		for (; i < N / 2; i++) {
			if (S[i] != S[i + N / 2]) break;
		}
		if (i == N / 2) {
			printf("Yes");
			return 0;
		}
	}
	printf("No");
	return 0;
}