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 Rust (1.15.1) (judge verdict: Accepted)

#[allow(dead_code)]
fn read_line(n: usize) -> String {
    let mut ss = String::new();
    for _i in 0..n {
        let mut s = String::new();
        std::io::stdin().read_line(&mut s).unwrap();
        ss.push_str(&s);
    }
    ss
}

macro_rules! parse {
    ($s:expr => $($r:tt)*) => {
        let s = $s;
        let mut iter = s.split_whitespace();
        input_inner!{iter, $($r)*}
    };
    ($($r:tt)*) => {
        use std::io::Read;
        let mut s = String::new();
        std::io::stdin().read_to_string(&mut s).unwrap();
        parse!{s => $($r)*}
    };
}

macro_rules! input_inner {
    ($iter:expr) => {};
    ($iter:expr, ) => {};
    ($iter:expr, $var:ident : $t:tt $($r:tt)*) => {
        let $var = read_value!($iter, $t);
        input_inner!{$iter $($r)*}
    };
    ($iter:expr, mut $var:ident : $t:tt $($r:tt)*) => {
        let mut $var = read_value!($iter, $t);
        input_inner!{$iter $($r)*}
    };
}

macro_rules! read_value {
    ($iter:expr, ( $($t:tt),* )) => {
        ( $(read_value!($iter, $t)),* )
    };
    ($iter:expr, [ $t:tt ; $len:expr ]) => {
        (0..$len).map(|_| read_value!($iter, $t)).collect::<Vec<_>>()
    };
    ($iter:expr, chars) => {
        read_value!($iter, String).chars().collect::<Vec<char>>()
    };
    ($iter:expr, usize1) => {
        read_value!($iter, usize) - 1
    };
    ($iter:expr, $t:ty) => {
        $iter.next().unwrap().parse::<$t>().expect("Parse error")
    };
}

fn sub() -> bool
{
    parse!{
        n: usize,
        s: chars,
    }
    if n % 2 != 0 {
        return false;
    }
    let mut a = String::new();
    for i in 0..n / 2 {
        a.push(s[i]);
    }
    let mut b = String::new();
    for i in n / 2..n {
        b.push(s[i]);
    }
    return a == b;
}

fn main()
{
    if sub() {
        println!("Yes");
    }
    else {
        println!("No");
    }
}