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 9.2.1) (judge verdict: Accepted)

#include<stdio.h>
#include<string.h>

#define max 1000
 
int main(){
  int len;
  char str[max];
  
  scanf("%d", &len);
  scanf("%s", str);
  
  if(len % 2 == 1){
    printf("No\n");
    return 0;
  }else{
    int i;
    int n = len/2;
    int count = 0;
    
    for(i = 0; i < n; i++){
      if(str[i] == str[i+n]){
        count++;
      }
    }
    if(count == n){
      printf("Yes\n");
      return 0;
    }else{
      printf("No\n");
    }
  }
}