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>
#include <math.h>
#include <stdlib.h>

int main() {
  	int n, i, ok = 1;
  	char palavra[105];
  	scanf("%d\n%s\n", &n, palavra);
  	if(n % 2 == 1){
    	printf("No\n");
    }else{
      n = n >> 1;
      for(i = 0; i < n; i++){
      	if(palavra[i] != palavra[i + n])
          ok = 0;
      }
      if(ok){
      	printf("Yes\n");
      }else{
        printf("No\n");
      }
    }
	return 0;
}