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<stdlib.h>
#include<string.h>
#include<math.h>
#include<time.h>
#include<ctype.h>
    char ch[201];
int main(){
    int n, i, j, cnt=0, a;
    scanf("%d", &n);
    scanf("%s", &ch);
    if(n%2==0){
    for(i=0, j=(n/2);i<(n/2),j<n;i++,j++){

            if(ch[i]==ch[j]){
                cnt++;

            }

    }
    if(cnt==ceil(n/2))
        printf("Yes");
    else
        printf("No");
    }
    else
        printf("No");

return 0;
}