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;
 
#define INPUT_OUTPUT { \
	freopen("input.txt", "r", stdin); \
	freopen("output.txt", "w", stdout); \
}
#define ll long long
#define Pi acos(-1)
 
int main()
{
	//INPUT_OUTPUT;
	int n, i;
	string s, t;
	cin >> n;
	cin >> s;
	int mid = n/2;
	for(i = 0; i < mid; i++) {
		t += s.at(i);
	}
	if(s.substr(mid,n) == t) cout << "Yes" << endl;
	else cout << "No" << endl;
	return 0;
}