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: Accepted)

#include<stdio.h>
#include<string.h>
int main()
{
    int n,i,j,f=0;
    scanf("%d ",&n);
    char str[n+1];
    gets(str);
    if(n%2!=0)
        printf("No\n");
    else
    {
        for(i=0,j=n/2; i<n/2; i++,j++)
        {
            if(str[i]!=str[j])
            {
                f=1;
                break;
            }
        }

        if(f==1)
            printf("No");
        else
            printf("Yes");

    }
    return 0;
}