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)

#pragma GCC optimize ("O3")
#include <bits/stdc++.h>
#define ll long long
#define ld long double
#define oo (int)1e7
#define IO ios_base::sync_with_stdio(0),cin.tie(0),cout.tie(0);
using namespace std;
const int N = 1e2 + 5, M = 1e5 + 5;

int main(){
    int n;
    cin >> n;
    string s;
    cin >> s;
    if(n & 1){
        puts("No");
        return 0;
    }
    string k;
    for(int i = 0 ; i < n / 2 ; ++i){
        k += s.back();
        s.pop_back();
    }
    reverse(k.begin(), k.end());
    puts(s == k ? "Yes" : "No");
}