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)

/*
Program		: echo.c
Description	: Checking echo of a string
Author		: Rey Rizki
Date		: 16 November 2019
Time        : 7:58 P.M. to 
Compiler	: gcc Ubuntu 7.4.0
*/

#include <stdio.h>
#include <string.h>
#include <stdbool.h>

int main() {
    // DECLARATION
    int length;                     // The length of the string
    char string[101];               // The string itself
    int i;                          // for iteration, as usual
    bool echo;                      // for the state

    // INPUT
    scanf("%d\n", &length);
    fgets(string, 101, stdin);

    // PROCESS
    echo = true;
    if (length % 2 == 0) {
        while (echo && i < length/2) {
            if (string[i] != string[i+(length/2)]) {
                echo = false;
            } else {
                i++;
            }
        }
    } else {
        echo = false;
    }

    // OUTPUT
    if (echo) {
        printf("Yes\n");
    } else {
        printf("No\n");
    }

    return 0;
}