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()
{
    int n,j,k,i,cnt=1;
    cin>>n;
    string a,b,s;
    cin>>s;
    if(n%2==1)
    {
        cout<<"No\n";
        return 0;
    }
    else
    for(i=0; i<n/2; i++)
    {
            a[i]=s[i];
    }
    for(i=n/2; i<=n; i++)
    {
            b[i]=s[i];
    }
    for(i=0;i<n/2-1;i++)
    {
        for(j=i+1; j<n ; j++)
        {
            if(a[i] == b[j])
            {
                cnt++;
            }

        }
    }
    if(cnt == n/2)
    {
        cout<<"Yes\n";
    }
    else
    {
        cout<<"No\n";
    }

}