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)
using namespace std;
typedef long long ll;

int main(){
    int n;
    cin >> n;
    vector<char> s(n);
    rep(i,n)  cin >> s.at(i);
    if(n%2 == 1){
        cout << "No" << endl;
        return 0;
    }

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

    cout << "Yes" << endl;
    
    return 0;
}