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 <iostream>
#include <vector>
using namespace std;

int main(void) {
    int n;
    cin >> n;
    vector<char> r(n + 5);
    for(int i = 0; i < n; i++) {
        cin >> r[i];
    }
    int count = 0;
    for(int i =0; i < n; i++) {
        if(r[i] == r[i +n/2]) {
            count++;
        }
    }
    if(count == n / 2) {
        cout << "Yes" << endl;
    } else {
        cout << "No" << endl;
    }
}