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: Wrong Answer)

#include <bits/stdc++.h>
using namespace std;

int main() {
	// your code goes here
     int n;
     cin>>n;
     
          string str;
          cin>>str;
          if(n%2==1){
               cout<<"No"<<endl;
          }else{
          
          bool flag;
          for(int i=0,j=n/2;i<n,j<n;i++,j++){
               if(str[i]!=str[j]){
                    flag=true;
               }
          }

          if(flag){
               cout<<"No"<<endl;
          }else{
               cout<<"Yes"<<endl;
          }
     }
     
	return 0;
}