C# 线性表的实现

      线性表的基本操作定义如下：
      

    public interface IListDS<T>
    {
        int GetLength();
        void Clear();
        bool IsEmpty();
        void Append(T item);
        void Insert(T item, int i);
        T Delete(int i);
        T GetElem(int i);
        int Locate(T value);
        void Reverse();
        void Print();
    }

      （1）：顺序表的定义：指内存中用一块连续的空间依次存储线性表的每个元素。因为在C#中数组在内存中占用的存储空间就是一组连续的存储区域，具有随机存储的特点，逻辑上相邻的数据元素物理上也相邻。代码实现如下：
      

    public class SeqList<T>:IListDS<T>
    {
        private int maxSize;
        private T[] data;
        private int last;

        public T this[int index]
        {
            get { return data[index]; }
            set { data[index] = value; }
        }

        public int Last
        {
            set { last = value; }
            get { return last; }
        }

        public int MaxSize
        {
            set { maxSize = value; }
            get { return maxSize; }
        }

        public SeqList(int size)
        {
            data = new T[size];
            maxSize = size;
            last = -1;
        }

        public int GetLength()
        {
            return last + 1;
        }

        public void Clear()
        {
            last = -1;
        }

        public bool IsEmpty()
        {
            if (last == -1)
                return true;
            else
                return false;
        }

        public bool IsFull()
        {
            if (last == (maxSize - 1))
                return true;
            else
                return false;
        }

        public void Append(T item)
        {
            if (IsFull())
            {
                Console.WriteLine("List Is Full!");
                return;
            }

            data[++last] = item;
        }

        public void Insert(T item, int i)
        {
            if (IsFull())
            {
                Console.WriteLine("List Is Full!");
                return;
            }
            if (i < 1 || i > last + 2)
            {
                Console.WriteLine("Position error!");
                return;
            }
            if (i == last + 2)
            {
                data[++last] = item;
            }
            else
            {
                for (int j = last; j >=i-1; j--)
                {
                    data[j + 1] = data[j];
                }
                data[i - 1] = item;
                ++last;
            }
        }

        public T Delete(int i)
        {
            T temp = default(T);
            if (IsEmpty())
            {
                Console.WriteLine("List is empty!");
                return temp;
            }
            if (i < 1 || i > last + 1)
            {
                Console.WriteLine("Position is error!");
                return temp;
            }
            if (i == last + 1)
            {
                temp = data[last];
            }
            else
            {
                temp = data[i - 1];
                for (int j = i-1; j < last; j++)
                {
                    data[j] = data[j + 1];
                }
            }
            --last;
            return temp;
        }

        public T GetElem(int i)
        {
            if (IsEmpty() || (i < 1) || (i > last + 1))
            {
                Console.WriteLine("List is empty or position is error!");
                return default(T);
            }
            else
            {
                return data[i - 1];
            }
        }

        public int Locate(T value)
        {
            if (IsEmpty())
            {
                Console.WriteLine("List is empty!");
                return -1;
            }
            int i = 0;
            for (i = 0; i <= last; i++)
            {
                if(value.Equals(data[i]))
                {
                    break;
                }
            }
            if (i > last)
            {
                return -1;
            }
            return i;
        }

        public void Reverse()
        {
            T temp = default(T);
            int len = GetLength()-1;
            for (int i = 0; i <= len/2; i++)
            {
                temp = data[i];
                data[i] = data[len - i];
                data[len - i] = temp;
            }
        }

        public void Print()
        {
            for (int i = 0; i <= last; i++)
            {
                Console.Write("  " + data[i]);
            }
            Console.WriteLine();
        }

    }

      注释：maxSize表示顺序表的容量，data存储顺序表的元素，last指示最后一个元素的位置。
      a.插入操作：判断顺序表是否已满和插入的位置是否正确，表满或者插入的顺序不正确不能插入；如果表满或者插入的位置的正确，咋将a1~~ai依次向后移动，为新的数据元素空出位置，用循环来实现；将新的元素插入到空出的第i位置上；修改last,使它指向顺序表的最后一个元素。插入的时间复杂度O（N）。
      b.删除元素：判断顺序表是否为空和删除的位置是否合理，表空或删除的位置不合理，不能删除；如果表不空和删除的位置正确，则将a1~ai依次向前移动，用循环来实现；修改last指针，使它指向顺序表的最后一个元素。时间复杂度为O(N)。
      （2）：单链表是指用一组任意的存储单元来存储线性表中的数据元素。
        

    public class Node<T>
    {
        private T data;
        private Node<T> next;

        public T Data
        {
            set { data = value; }
            get { return data; }
        }
        public Node<T> Next
        {
            set { next = value; }
            get { return next; }
        }

        public Node(T val,Node<T> p)
        {
            data = val;
            next = p;
        }

        public Node(Node<T> p)
        {
            next = p;
        }

        public Node(T val)
        {
            data = val;
            next = null;
        }

        public Node()
        {
            data = default(T);
            next = null;
        }
    }

      

   public class LinkList<T>:IListDS<T>
    {
        private Node<T> head;
        public Node<T> Head
        {
            set { head = value; }
            get { return head; }
        }

        public LinkList()
        {
            head = null;
        }

        public int GetLength()
        {
            int len = 0;
            Node<T> p = head;
            while (p != null)
            {
                ++len;
                p = p.Next;
            }
            return len;
        }

        public void Clear()
        {
            head = null;
        }

        public bool IsEmpty()
        {
            if (head == null)
                return true;
            else
                return false;
        }

        public void Append(T item)
        {
            Node<T> q = new Node<T>(item);
            Node<T> p = new Node<T>();

            if (head == null)
            {
                head.Next = q;
                return;
            }

            p = head;
            while (p.Next != null)
            {
                p = p.Next;
            }

            p.Next = q;
        }

        public void Insert(T item, int i)
        {
            if (IsEmpty() || i < 1)
            {
                Console.WriteLine("LinkList is empty or position is error!");
                return;
            }
            if (i == 1)
            {
                Node<T> q = new Node<T>(item);
                q.Next = head;
                head = q;
                return;
            }
            Node<T> p = head;
            Node<T> r = new Node<T>();
            int j = 1;
            while (p.Next != null && j < i)
            {
                ++j;
                r = p;
                p = p.Next;
            }
            if (j == i)
            {
                Node<T> q = new Node<T>(item);
                q.Next = p;
                r.Next = q;
            }
            else
            {
                Console.WriteLine("Positon is error!");
            }
            return;
        }

        public T Delete(int i)
        {
            if (IsEmpty() || i < 0)
            {
                Console.WriteLine("LinkList is empty or position is error!");
                return default(T);
            }

            Node<T> q = new Node<T>();
            if (i == 1)
            {
                q = head;
                head = head.Next;
                return q.Data;
            }

            Node<T> p = head;
            int j = 1;
            while (p.Next != null && j < i)
            {
                ++j;
                q = p;
                p = p.Next;
            }
            if (j == i)
            {
                q = p.Next;
                return p.Data;
            }
            else
            {
                Console.WriteLine("Position is error!");
                return default(T);
            }
        }

        public T GetElem(int i)
        {
            if (IsEmpty())
            {
                Console.WriteLine("Linklist is empty!");
                return default(T);
            }

            Node<T> p = head;
            int j = 1;
            while (p.Next != null && j < i)
            {
                ++j;
                p = p.Next;
            }
            if (j == i)
            {
                return p.Data;
            }
            else
            {
                Console.WriteLine("Position is error!");
                return default(T);
            }
        }

        public int Locate(T value)
        {
            if (IsEmpty())
            {
                Console.WriteLine("LinkList is empty!");
                return -1;
            }

            Node<T> p = head;
            int i = 1;
            while (!p.Data.Equals(value) && p.Next != null)
            {
                ++i;
                p = p.Next;
            }
            return i;
        }

        public void Reverse()
        {
            Node<T> p = head;
            Node<T> q = new Node<T>();
            Node<T> R = new Node<T>();
            while (p != null)
            {
                q = p;
                p = p.Next;
                q.Next = R.Next;
                R.Next = q;
            }
            head = R.Next;
            R = null;
        }

        public void Print()
        {
            Node<T> p = head;
            if (p != null)
            {
                while (p != null)
                {
                    Console.Write("  " + p.Data);
                    p = p.Next;
                }
                Console.WriteLine();
            }
            else
            {
                Console.WriteLine("LinkList is empty!");
            }
        }

    }

      注释：线性表的顺序存储和链式存储各有优缺点，线性表如何存储取决于使用场合。如果不需要经常在线性表中进行插入和删除，那么线性表适合顺序存储；如果线性表需要经常插入和删除，而不经常查找，则应链式存储。
       a.插入操作：前插操作和后插操作，时间复杂度：O(N)。
       b. 删除操作，时间复杂度O(N)
      (3):单链表的创建
            1）：在单链表的头部插入节点建立
            2）：在单链表的尾部插入节点建立
     （4）：双链表
     （5）：循环链表