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 rep(i, n) for (int i = 0; i < (int)(n); i++)
typedef long long ll;

int main() {
    int n; cin >> n;
    string S; cin >> S;
    bool ans = true;
    if(n % 2 != 0){
        cout << "No" << endl;
        return 0;
    }else{
        rep(i,n/2){
            if(S[i] != S[n/2 + i]){
                ans = false;
            }
        }
    }
    if(ans) cout << "Yes" << endl;
    else cout << "No" << endl;
}