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;
    char str[100];
    char strA[50];

    scanf("%d", &n);
    scanf("%*c%s", str);

    for (int i = 0; i < n;i++){
        if(i<n/2){
            strA[i] = str[i];
        }
        else{
            str[i - (n-1)] = str[i];
            str[i] = 0;
        }
    }

    if(strncmp(strA,str,n/2)==0 && n%2==0)
        printf("Yes\n");
    else if(n%2==1)
        printf("No\n");
    else
        printf("No\n");
    return 0;
}