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 benfero freopen("input.txt","r",stdin); freopen("output.txt","w",stdout);
#define mm ' '
#define nl '\n'
#define MOD 1000007
typedef unsigned long long int ull;
typedef long long int ll;
int main()
{
    //benfero
    int n;
    string s;
    cin>>n>>s;
    if(n%2){cout<<"No"<<nl; return 0;}
    int idx=n/2;
    int i;
    for(i=0;i<(n/2);i++){
        if(s[i]!=s[idx++]){cout<<"No"<<nl; return 0;}
    }
    cout<<"Yes"<<nl;
    return 0;
}