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 9.2.1) (judge verdict: Accepted)

#include<bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
using namespace std;

typedef long long ll;
typedef pair<int,int> ii;
typedef tree<ii,null_type,less<ii>,rb_tree_tag,tree_order_statistics_node_update> indexed_set;

int main() {
	cin.tie(0); cout.tie(0); ios_base::sync_with_stdio(0);
	int n; cin>>n;
	string s; cin>>s;
	string t=s.substr(0,s.size()/2);
	if (t+t==s) cout<<"Yes";
	else cout<<"No"<<endl;
	return 0;
}