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: Accepted)

#include <stdio.h>
#define MAX_SIZE 101

int solve(char s[], int n) {
    int i;
    if(n & 1) return 0;
    for(i = 0; s[i] == s[n / 2 + i]; i ++);
    
    return i == n / 2;
}

int main() {
    int n, result;
    char s[MAX_SIZE];
    
    scanf("%d\n", &n);
    gets(s);

    result = solve(s, n);

    if (result)
        puts("Yes");
    else
        puts("No");
}