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>
#include<stdlib.h>

int main()
{
    int n,i,flag=0;
    char str[100];
    printf("Enter the number of charcters in the string:\n");
    scanf("%d",&n);
    
    if(n%2!=0)
    {
        printf("Enter even length");
        exit(0);
    }
    else
    {
        printf("Enter the string:\n");
        scanf("%s",str);
        for(i=0;i<n/2;i++)
        {
            if(str[i]!=str[(strlen(str))/2+i])
            {
               flag=0;
               break;
            }
          flag=1;
        }
    
    }
    if(flag)
    printf("Yes");
    else
    printf("No");
    return 0;
}