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 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <stdio.h>
#include <string.h>

#define max 100

int main()
{
    int N, i, cnt=0;
    char S[max];
    
    scanf("%d %s", &N, S);
    
    if(N%2!=0){
        printf("No");
        return 0;
    }
    
    for (i=0; i<N/2; i++) {
        if (S[i]==S[i+N/2]) {
            cnt++;
        }
    }
    
    if(cnt!=0)
        printf("Yes");
    else
        printf("No");
    
    return 0;
}