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: Wrong Answer)

#include <stdio.h>

int main(void){
   int n,point,i,result=0;
   char str[101];

   scanf("%d%s",&n,str);
   point = n/2;
   if(n==1){printf("No\n"); return 0;}

   for(i=0;i<point;i++)
      if(str[i]!=str[i+point]){result=1;break;}

   if(result==0) printf("Yes\n");
   else printf("No\n");
   return 0;
}