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 <stdlib.h>
 
int main()
{
    int n;
    char s[105];
    scanf("%d",&n);
    scanf("%s",s);
    int i;
 
    if(n%2!=0)
    {
        printf("No");
    }
    else
    {
        int a=n/2;
        for(i=0; i<a; i++)
        {
            if(s[i]!=s[i+a])
            {
                printf("No");
            }
        }
        printf("Yes");
 
    }
    return 0;
}