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 <iostream>
#include <string>
#include <vector>
#include <map>
#include <set>
#include <list>
#include <algorithm>
#include <cmath>
#include <iomanip>
 
 
int main()
{
    int n; std::string s;
    std::cin >> n >> s;
    if(n%2==1)
    {
        
    }
    else
    {
        if(s.substr(0, n/2)==s.substr(n/2, n/2))
        {
            std::cout << "Yes" << std::endl;
            return 0;
        }
    }
    std::cout << "No" << std::endl;
    return 0;
}