import java.util.*;

public class Task171025 {
    public static void main(String[] args) {
        Queue<Integer> queue = new LinkedList<>();
        queue.offer(1);
        queue.offer(2);
        queue.offer(3);
        
        System.out.print(queue.peek() + " ");
        System.out.print(queue.poll() + " ");
        queue.offer(4);
        System.out.print(queue.remove() + " ");
        System.out.print(queue.element() + " ");
    }
}

import java.util.Optional;

public class Task201025 {
    public static void main(String[] args) {
        Optional<String> optional = Optional.of("hello");
        Optional<String> filtered = optional.filter(s -> s.length() > 10);
        Optional<String> mapped = optional.map(s -> null);
        
        System.out.println(filtered.isPresent());
        System.out.println(mapped.isPresent());
        System.out.println(optional.orElse("world"));
        System.out.println(filtered.orElse("java"));
    }
}

import java.util.PriorityQueue;

public class Task211025 {
    public static void main(String[] args) {
        PriorityQueue<Integer> pq = new PriorityQueue<>();
        pq.offer(5);
        pq.offer(2);
        pq.offer(8);
        pq.offer(1);
        
        System.out.print(pq.poll() + " ");
        System.out.print(pq.poll() + " ");
        
        pq.offer(0);
        pq.offer(3);
        
        System.out.print(pq.poll() + " ");
        System.out.print(pq.poll() + " ");
        System.out.print(pq.poll());
    }
}

import java.util.LinkedList;

public class Task221025 {
    public static void main(String[] args) {
        LinkedList<Integer> list = new LinkedList<>();
        list.add(1);
        list.add(2);
        list.add(3);
        
        list.remove(1);
        list.remove(new Integer(2));
        
        System.out.println(list.size());
        System.out.println(list.get(0));
    }
}

import java.util.ArrayDeque;
import java.util.Deque;

public class Task231025 {
    public static void main(String[] args) {
        Deque<Integer> deque = new ArrayDeque<>();
        deque.offer(1);
        deque.push(2);
        deque.offer(3);
        deque.push(4);
        
        System.out.print(deque.poll() + " ");
        System.out.print(deque.pop() + " ");
        System.out.print(deque.remove() + " ");
        System.out.print(deque.element());
    }
}

import java.util.concurrent.*;

public class Task241025 {
    public static void main(String[] args) throws InterruptedException {
        BlockingQueue<Integer> queue = new ArrayBlockingQueue<>(2);
        
        System.out.print(queue.offer(1) + " ");
        System.out.print(queue.offer(2) + " ");
        System.out.print(queue.offer(3, 100, TimeUnit.MILLISECONDS) + " ");
        
        System.out.print(queue.poll() + " ");
        System.out.print(queue.offer(3) + " ");
        System.out.print(queue.poll() + " ");
        System.out.print(queue.poll() + " ");
    }
}