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 <bits/stdc++.h>
using namespace std;

int main() {
	int n; cin >> n;
	vector<char> s(n);	for (int i = 0; i < n; i++) { cin >> s[i]; }
	if (s.size() % 2 != 0) {
		cout << "No" << endl;
		return 0;
	}

	int mid = n / 2;
	for (int i = 0; i < mid; i++) {
		if (s[i] != s[mid + i]) {
			cout << "No" << endl;
			return 0;
		}
	}

	cout << "Yes" << endl;
}