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>

typedef long long ll;

#define min(a, b) ((a) < (b)) ? (a) : (b)
#define max(a, b) ((a) > (b)) ? (a) : (b)
#define swap(a, b, typ) \
    do { \
        typ tmp = a; \
        a = b; \
        b = tmp; \
    } while (0)

#define MAX_N 100

int main(void) {
    int n;
    char s[MAX_N + 1];

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

    if (n % 2 == 1) {
        printf("No\n");
        return 0;
    }

    for (int i = 0; i < n / 2; i++) {
        if (s[i] != s[i + n / 2]) {
            printf("No\n");
            return 0;
        }
    }

    printf("Yes\n");
    return 0;
}