两个栈构造一个队列 || 两个队列构造一个栈
这篇文章主要用于理解队列(Queue)与栈(Stack)的区别与联系,区别在于队列(Queue)是先进先出(FIFO),而栈(Stack)是先进后出(FILO);同样的,两则都为线性存储结构。一. 两个栈构造一个队列:Queue with two stacks(Stack 1:inbox,Stack 2: outbox)
入列操作(EnQueue)
inbox压栈。
出列操作(DeQueue)
判断inbox为空则抛出InvalidOperationException异常;
否则,将inbox所有数据出栈,并且压入outbox;
outbox出栈一次,并且把数据存入临时变量temp;
将outbox剩下所有数据出栈重新压入inbox;
返回temp。
以上为思路,附上C#代码如下:
using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace TestApp.QueueAndStack { /// <summary> /// Construct a queue with two stacks: FIFO /// </summary> /// <typeparam name="T"></typeparam> public class Queue2Ss<T> { private Stack<T> inbox = null; private Stack<T> outbox = null; /// <summary> /// Initialize the two stacks /// </summary> public Queue2Ss() { inbox = new Stack<T>(); outbox = new Stack<T>(); } /// <summary> /// EnQueue /// </summary> /// <param name="t"></param> public void EnQueue(T t) { inbox.Push(t); } /// <summary> /// DeQueue /// </summary> /// <returns></returns> public T DeQueue() { if (inbox.Count == 0) { throw new InvalidOperationException("The queue is empty."); } // Pop the values of inbox to outbox while (inbox.Count > 0) { outbox.Push(inbox.Pop()); } // Get the result T t = outbox.Pop(); // Push to inbox with the values of outbox while (outbox.Count>0) { inbox.Push(outbox.Pop()); } return t; } /// <summary> /// Clear the whole queue's values /// </summary> public void Clear() { inbox.Clear(); outbox.Clear(); } /// <summary> /// Return the count of queue /// </summary> /// <returns></returns> public int Count() { return (inbox.Count + outbox.Count); } } }
二. 两个队列构造一个栈:Stack with two queues(Queue 1: inbox,Queue 2: outbox)
压栈操作(Push)
inbox入列。
出栈操作(Pop)
判断inbox为空则抛出InvalidOperationException异常;
否则,将inbox数据出列直到剩下最后一个元素为止,并且将出列数据入列到outbox中;
inbox出列一次,并且将数据存入临时变量temp;
Swap(inbox,outbox);
返回temp。
附上C#代码如下:
using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace TestApp.QueueAndStack { /// <summary> /// Construct a stack with two queues: FILO /// </summary> public class Stack2Qs<T> { private Queue<T> inbox = null; private Queue<T> outbox = null; /// <summary> /// Initialize the two queues /// </summary> public Stack2Qs() { inbox = new Queue<T>(); outbox = new Queue<T>(); } /// <summary> /// Push /// </summary> /// <param name="t"></param> public void Push(T t) { inbox.Enqueue(t); } /// <summary> /// Pop /// </summary> /// <returns></returns> public T Pop() { if (inbox.Count == 0) { throw new InvalidOperationException("The stack is empty."); } // Dequeue the inbox's values to outbox // until the inbox has only 1 element left while (inbox.Count > 1) { outbox.Enqueue(inbox.Dequeue()); } // Get the result T t = inbox.Dequeue(); // Exchange the inbox and the outbox Queue<T> temp = inbox; inbox = outbox; outbox = temp; return t; } /// <summary> /// Clear the whole stack's values /// </summary> public void Clear() { inbox.Clear(); outbox.Clear(); } /// <summary> /// Return the count of stack /// </summary> /// <returns></returns> public int Count() { return (inbox.Count + outbox.Count); } } }
上面是基于对栈和队列的理解的基础上,分别对栈和队列的实现,当然我们也可以利用C#里面的线性链表分别对Stack和Queue进行实现,有兴趣大家可以试试,so easy!妈妈再也不用担心我不会栈和队列了!~_~
补充:软件开发 , C# ,