Stack 두개를 이용하여 Queue구현하기

Stack 두개를 이용하여 Queue구현하기

 

https://www.interviewbit.com/blog/implement-queue-using-stack/

 

• 자바

import java.util.Stack;

class Queue<T> {
  Stack<T> inStack;
  Stack<T> outStack;

  public Queue() {
    this.inStack = new Stack<>();
    this.outStack = new Stack<>();
  }

  public void enqueue(T value) {
    inStack.add(value);
  }

  public T dequeue() {
    if (!inStack.isEmpty()) {
      while(!inStack.isEmpty()) {
        outStack.add(inStack.pop());
      }
    }
    return outStack.pop();
  }

  @Override
  public String toString() {
    return "Queue{" +
        "inStack=" + inStack +
        ", outStack=" + outStack +
        '}';
  }
}

public class Main {

  public static void main(String[] args) {
    Queue<Integer> queue = new Queue<>();
    queue.enqueue(1);
    queue.enqueue(2);
    queue.enqueue(3);
    queue.enqueue(4);
    queue.enqueue(5);

    System.out.println(queue);

    System.out.println(queue.dequeue());
  }
}