[코딩인터뷰] 문제 3.5

문제 3.5

	#region Question 3.5
	/*
	* 두 개의 스택을 사용하여 큐를 구현하는 MyQueue 클래스를 작성해보라.
	*/
	/// <summary>
	/// 두 개의 스택으로 구현한 큐 자료구조
	/// </summary>
	/// <typeparam name="T">저장할 데이터 타입</typeparam>
	public class MyQueue<T>
	{
	private readonly Stack<T> stackEnqueue;
	private readonly Stack<T> stackDequeue;
	public MyQueue()
	{
	stackEnqueue = new Stack<T>();
	stackDequeue = new Stack<T>();
	}
	public int Size()
	{
	return stackEnqueue.Count + stackDequeue.Count;
	}
	public void Enqueue(T value)
	{
	stackEnqueue.Push(value);
	}
	private void SwitchStack()
	{
	// 꺼낼 스택이 비어있을 때만 스택 데이터를 옮긴다.
	if (stackDequeue.Count == 0)
	{
	while (stackEnqueue.Count != 0)
	{
	stackDequeue.Push(stackEnqueue.Pop());
	}
	}
	}
	public T Peek()
	{
	SwitchStack();
	return stackDequeue.Peek();
	}
	public T Dequeue()
	{
	SwitchStack();
	return stackDequeue.Pop();
	}
	}
	#endregion

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	[TestMethod]
	public void Q3_5()
	{
	var myQueue = new StackQueue.MyQueue<int>();
	myQueue.Enqueue(1);
	myQueue.Enqueue(2);
	Assert.AreEqual(1, myQueue.Peek());
	Assert.AreEqual(1, myQueue.Dequeue());
	myQueue.Enqueue(3);
	Assert.AreEqual(2, myQueue.Dequeue());
	Assert.AreEqual(3, myQueue.Peek());
	myQueue.Enqueue(4);
	Assert.AreEqual(3, myQueue.Peek());
	Assert.AreEqual(3, myQueue.Dequeue());
	Assert.AreEqual(4, myQueue.Dequeue());
	}

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