队列c#版

一. 顺序队列

  在顺序队列中，我们维护一个头指针和尾指针来避免每一次出队都要移动数组，而仅仅在入队时发现空间不足时，在尝试进行移动数组操作，将空余的位置利用起来。

    public class MyQueue<T>
    {
        T[] data;  // 数据
        int front = 0;  // 前指针
        int rear = 0;   // 后指针

        public MyQueue(int size)
        {
            data = new T[size];
        }

        /// <summary>
        /// 入队
        /// </summary>
        /// <param name="model"></param>
        public void Enqueue(T model)
        {
            if (rear < data.Length)
                data[rear] = model;
            else
            {
                if (front > 0)
                {
                    Move();
                    data[rear] = model;
                }
                else
                    throw new ArgumentOutOfRangeException("超出队列长度");
            }
            
            rear++;
        }

        

        /// <summary>
        /// 出队
        /// </summary>
        /// <returns></returns>
        public T Dequeue()
        {
            T result = default(T);
            if (rear > front)
                result = data[front];
            else
                throw new NullReferenceException("队列中没有值");
            front++;
            return result;
        }

        public bool IsEmpty()
        {
            return front == rear;
        }

        public bool IsFull()
        {
            return rear == data.Length;
        }

        public int Length => data.Length;

        public int ItemLength => rear - front;

        private void Move()
        {
            var itemlength = ItemLength;
            // 移动队列，将下标为0的前数组填满
            for (int i = 0; i < itemlength; i++)
            {
                data[i] = data[front];
                front++;
            }
            front = 0;
            rear = itemlength;
        }

View Code

测试代码：

 1 try
 2  {
 3         MyQueue<int> queue = new MyQueue<int>(3);
 4         queue.Enqueue(1);
 5         queue.Enqueue(2);
 6         queue.Enqueue(3);
 7         for (int i = 0; i < queue.Length; i++)
 8         {
 9             Console.WriteLine(queue.Dequeue());
10          }
11          queue.Enqueue(4);
12          queue.Enqueue(5);
13          queue.Enqueue(6);
14          Console.WriteLine(queue.Dequeue());
15          queue.Enqueue(7);
16          Console.WriteLine(queue.Dequeue());
17          Console.WriteLine(queue.Dequeue());
18          queue.Enqueue(8);
19          queue.Enqueue(9);
20          queue.Enqueue(10);
21          queue.Enqueue(11);
22 }
23 catch (ArgumentOutOfRangeException e)
24 {
25         Console.WriteLine(nameof(ArgumentOutOfRangeException) + e.Message);
26 }
27 catch (NullReferenceException e)
28 {
29         Console.WriteLine(nameof(NullReferenceException) + e.Message);
30 }    

View Code