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;

int main(){

    string S;
    int N=0;
    bool b=true;
    cin >> N;
    cin >> S;
    if(N%2==0){
        for(int i=0;i<N/2;i++){
            if(S.at(i)!=S.at(i+N/2)){
                b = false;
            }
        }
    }
    else{
        b=false;
    }
if(b==true){
    cout << "Yes" << endl;
}
else{
    cout << "No" << endl;
}
}