Java by API/java.util/Deque

Deque: isEmpty()

 
import java.util.ArrayDeque;
import java.util.Deque;
public class Main {
  public static void main(String args[]) {
    Deque<String> stack = new ArrayDeque<String>();
    Deque<String> queue = new ArrayDeque<String>();
    stack.push("A");
    stack.push("B");
    stack.push("C");
    stack.push("D");
    while (!stack.isEmpty())
      System.out.print(stack.pop() + " ");
    queue.add("A");
    queue.add("B");
    queue.add("C");
    queue.add("D");
    while (!queue.isEmpty())
      System.out.print(queue.remove() + " ");
  }
}

Deque: peekFirst()

  
import java.util.ArrayDeque;
import java.util.Deque;
public class Main {
  public static void main(String[] args) {
    MyDequeue stack = new MyDequeue();
    for (int i = 0; i < 5; i++) {
      stack.push(i);
    }
    System.out.println("After pushing 5 elements: " + stack);
    int m = stack.pop();
    System.out.println("Popped element = " + m);
    System.out.println("After popping 1 element : " + stack);
    int n = stack.peek();
    System.out.println("Peeked element = " + n);
    System.out.println("After peeking 1 element : " + stack);
  }
}
class MyDequeue {
  private Deque<Integer> data = new ArrayDeque<Integer>();
  public void push(Integer element) {
    data.addFirst(element);
  }
  public Integer pop() {
    return data.removeFirst();
  }
  public Integer peek() {
    return data.peekFirst();
  }
  public String toString() {
    return data.toString();
  }
}

Deque: pop()

 
import java.util.ArrayDeque;
import java.util.Deque;
public class Main {
  public static void main(String args[]) {
    Deque<String> stack = new ArrayDeque<String>();
    Deque<String> queue = new ArrayDeque<String>();
    stack.push("A");
    stack.push("B");
    stack.push("C");
    stack.push("D");
    while (!stack.isEmpty())
      System.out.print(stack.pop() + " ");
    queue.add("A");
    queue.add("B");
    queue.add("C");
    queue.add("D");
    while (!queue.isEmpty())
      System.out.print(queue.remove() + " ");
  }
}

Deque: push(T e)

 
import java.util.ArrayDeque;
import java.util.Deque;
public class Main {
  public static void main(String args[]) {
    Deque<String> stack = new ArrayDeque<String>();
    Deque<String> queue = new ArrayDeque<String>();
    stack.push("A");
    stack.push("B");
    stack.push("C");
    stack.push("D");
    while (!stack.isEmpty())
      System.out.print(stack.pop() + " ");
    queue.add("A");
    queue.add("B");
    queue.add("C");
    queue.add("D");
    while (!queue.isEmpty())
      System.out.print(queue.remove() + " ");
  }
}

Deque: remove()

 
import java.util.ArrayDeque;
import java.util.Deque;
public class Main {
  public static void main(String args[]) {
    Deque<String> stack = new ArrayDeque<String>();
    Deque<String> queue = new ArrayDeque<String>();
    stack.push("A");
    stack.push("B");
    stack.push("C");
    stack.push("D");
    while (!stack.isEmpty())
      System.out.print(stack.pop() + " ");
    queue.add("A");
    queue.add("B");
    queue.add("C");
    queue.add("D");
    while (!queue.isEmpty())
      System.out.print(queue.remove() + " ");
  }
}

Deque: removeFirst()

  
import java.util.ArrayDeque;
import java.util.Deque;
public class Main {
  public static void main(String[] args) {
    MyDequeue stack = new MyDequeue();
    for (int i = 0; i < 5; i++) {
      stack.push(i);
    }
    System.out.println("After pushing 5 elements: " + stack);
    int m = stack.pop();
    System.out.println("Popped element = " + m);
    System.out.println("After popping 1 element : " + stack);
    int n = stack.peek();
    System.out.println("Peeked element = " + n);
    System.out.println("After peeking 1 element : " + stack);
  }
}
class MyDequeue {
  private Deque<Integer> data = new ArrayDeque<Integer>();
  public void push(Integer element) {
    data.addFirst(element);
  }
  public Integer pop() {
    return data.removeFirst();
  }
  public Integer peek() {
    return data.peekFirst();
  }
  public String toString() {
    return data.toString();
  }
}