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: Accepted)

#include <iostream>
#include <map>
#include <queue>
#include <cmath>
#include <vector>
#include <iostream>
#include <algorithm>
#include <functional>
using namespace std;
#pragma warning (disable: 4996)

int main() {
	int N; string S; cin >> N >> S;

	if (N % 2 == 1) cout << "No" << endl;
	else {
		string V1 = S.substr(0, N / 2);
		string V2 = S.substr(N / 2, N / 2);
		if (V1 == V2) cout << "Yes" << endl;
		else cout << "No" << endl;
	}
	return 0;
}