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, a;
    char s[101], t[51], c[51];

    scanf("%d %s",&n,s);

    if(n == 1){
        printf("No\n");
        return 0;
    }

    for(i=0; i<n/2; i++){   //文字列tを入力
        t[i] = s[i];
    }
    t[n/2] = '\0';

    for(i=0; i<n/2; i++){
        c[i] = s[n/2+i];
    }
    c[n/2] = '\0';
    
    a = strcmp(t,c);
    if(a == 0)
        printf("Yes\n");
    else
        printf("No\n");
    return 0;
}