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()
{
    char a[110],b[55]={0},c[55]={0};
    int n,mid,l,i,j;
    scanf("%d",&n);
    scanf("%s",&a);
    l=strlen(a);
    if(l%2!=0)
    {
        printf("No\n");
    }
    else
    {
        mid=l/2;
        for(i=0;i<mid;i++)
        {
            b[i]=a[i];
        }
        for(j=0,i=mid;i<l;i++,j++)
        {
            c[j]=a[i];
        }

        if(strcmp(b,c)==0)
            printf("Yes\n");
        else
            printf("No\n");
    }

}