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>
#include<string.h>

int main( void ){
    int n,i;
    char s[101];
    scanf("%d", &n);
    scanf("%s", s);
    char s1[51];
    char s2[51];
    if(n%2 == 0){
        for(i = 0; i < (n/2)-1; i++){
            s1[i] = s[i];
            s2[i] = s[(2/n)+i];
        }
    }
    if(strcmp(s1,s2) == 0){
        printf("Yes\n");
    } else {
        printf("No\n");
    }
    return 0;
}