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>
using namespace std;
int main(){
  	int n,flag=0;
  string x;	
  cin>>n>>x;
  if(n%2==1)
    flag=1;
   else{
  for(int i=0,j=n/2;i<n/2;i++,j++){
    if(x[i]!=x[j]){
      flag=1; break;
    }
}
   }  
    if(flag==1)
     cout<<"No";
     else
       cout<<"Yes";
}