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>
#define rep(i,n) for (int i=0; i<(n); i++)
#define repi(i,a,b) for (int i=a;i<(b);i++)
#define SIZE_OF_ARRAY(a) (sizeof(a)/sizeof(a[0]))
using namespace std;
typedef long long ll;
  
  int main(void){
    cin.tie(0);
    ios::sync_with_stdio(false);
	int n;
    string s;
    cin >> n >> s;
    if(n%2!=0){
      cout << "No" << endl;
      return 0;
    }
    string str_1 = s.substr(0,n/2);
    string str_2 = s.substr(n/2,n/2);
    if (str_1 == str_2){
      cout << "Yes" << endl;
    }else{
      cout << "No" << endl;
    }
    return 0;
  }