use std::collections::VecDeque;

fn main() {
    let mut deque = VecDeque::new();

    // push to back
    deque.push_back(1);
    deque.push_back(2);
    deque.push_back(3);

    // push to front
    deque.push_front(0);

    println!("deque: {:?}", deque);

    // pop from both ends
    println!("pop_front: {:?}", deque.pop_front());
    println!("pop_back: {:?}", deque.pop_back());
    println!("deque: {:?}", deque);

    // use as a sliding window
    let mut window = VecDeque::with_capacity(3);
    for i in 0..5 {
        if window.len() == 3 {
            window.pop_front();
        }
        window.push_back(i);
        println!("window: {:?}", window);
    }
}