use std::clone::Clone;
use std::cmp::PartialOrd;
use std::marker::Copy;
use std::vec::Vec;

fn merge<T: Clone + PartialOrd + Copy>(a: Vec<T>, b: Vec<T>) -> Vec<T> {
    let mut r = vec![];
    let mut i = 0;
    let mut j = 0;

    while i < a.len() && j < b.len() {
        if a[i] < b[j] {
            r.push(a[i]);
            i += 1;
        } else {
            r.push(b[j]);
            j += 1;
        }
    }

    while i < a.len() {
        r.push(a[i]);
        i += 1;
    }

    while j < b.len() {
        r.push(b[j]);
        j += 1;
    }

    return r;
}

fn merge_sort<T: Clone + PartialOrd + Copy>(v: Vec<T>) -> Vec<T> {
    if v.len() <= 1 {
        return v;
    }
    let i = v.len() / 2;
    let a = merge_sort((&v[..i]).to_vec());
    let b = merge_sort((&v[i..]).to_vec());
    let r = merge(a, b);
    return r;
}

fn mult_bin(a: i64, b: i64) -> i64 {
    return a * b;
}

fn main() {
    println!("Hello, world!");
    let l = vec![4, 2, 1, 3];
    let l = merge_sort(l);
    println!("{:?}", l);

    let r = mult_bin(42, 21);
    println!("{:?}", r);
}