extern crate itertools;
extern crate rand;
use rand::Rng;
use itertools::Itertools;
use std::time::Instant;

fn do_all_equal(v: &Vec<i32>) -> bool {
    v.iter().all_equal()
}
fn do_all_equal_for(v: &Vec<i32>) -> bool {
    for i in v {
        if i != &v[0] {
            return false;
        }
    }
    true
}
fn do_any_diff(v: &Vec<i32>) -> bool {
    v.iter().any(|x| x != &v[0])
}
fn main() {
    //let mut v = vec![0; 5_000_000];
    //v.extend(vec![1; 5_000_000]);
    let mut rng = rand::thread_rng();
    let mut v: Vec<i32> = (0..5_000_000).map(|_| rng.gen_range(1, 2)).collect();
    v.extend((0..5_000_000).map(|_| rng.gen_range(2, 3)) .collect::<Vec<i32>>());
    let mut start = Instant::now();
    do_all_equal(&v);
    let mut elapsed = start.elapsed();
    println!( "all_equal: {} msecs", elapsed.as_secs() * 1_000 + (elapsed.subsec_nanos() / 1_000_000) as u64);

    start = Instant::now();
    do_any_diff(&v);
    elapsed = start.elapsed();
    println!( "any_diff: {} msecs", elapsed.as_secs() * 1_000 + (elapsed.subsec_nanos() / 1_000_000) as u64);

    start = Instant::now();
    do_all_equal_for(&v);
    elapsed = start.elapsed();
    println!( "for loop: {} msecs", elapsed.as_secs() * 1_000 + (elapsed.subsec_nanos() / 1_000_000) as u64);
}