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,d,i;
    scanf("%d\n",&n);
    char s[n];
    gets(s);
    d=n/2;
    if(n%2!=0){
        printf("No\n");
    }
    else{
        for(i=0;i<d;i++){
            if(s[i]==s[i+d]){
                continue;
            }
            else{
                break;
            }
        }
        if(i==d){
            printf("Yes\n");
        }
        else{
            printf("No\n");
        }
    }
    return 0;
}