C# 实现 基于链表 LinkedListMap 的映射(Map)实现

public interface Map<K, V>
{
    void add(K key, V value);
    V remove(K key);
    bool contains(K key);
    V get(K key);
    void set(K key, V value);
    int getSize();
    bool isEmpty();
}

public class LinkedListMap<K, V> : Map<K, V>
{
    public class Node
    {
        public K key;
        public V value;
        public Node next;
        public Node(K key, V value, Node next)
        {
            this.key = key;
            this.value = value;
            this.next = next;
        }
        public Node(K key) : this(key, default(V), null) { }
        public Node() : this(default(K), default(V), null)
        {

        }
        public override string ToString()
        {
            return key.ToString() + ":" + value.ToString();
        }
    }
    private Node dummyHead;
    private int size;
    public LinkedListMap()
    {
        dummyHead = new Node();
        size = 0;
    }
    public void add(K key, V value)
    {
        var node = GetNode(key);
        if (node == null)
        {
            dummyHead.next = new Node(key, value, dummyHead.next);
            size++;
        }
        else
        {
            node.value = value;
        }
    }

    public bool contains(K key)
    {
        return GetNode(key) != null;
    }

    public V get(K key)
    {
        var node = GetNode(key);
        return node == null ? default(V) : node.value;
    }

    public int getSize()
    {
        return size;
    }

    public bool isEmpty()
    {
        return size == 0;
    }
    private Node GetNode(K key)
    {
        Node cur = dummyHead.next;
        while (cur != null)
        {
            if (cur.key.Equals(key))
            {
                return cur;
            }
            cur = cur.next;
        }
        return null;
    }
    public V remove(K key)
    {
        Node prev = dummyHead;
        while (prev.next != null)
        {
            if (prev.next.key.Equals(key))
            {
                break;
            }
            prev = prev.next;
        }
        if (prev.next != null)
        {
            Node deleNode = prev.next;
            prev.next = deleNode.next;
            deleNode.next = null;
            return deleNode.value;
        }
        return default(V);
    }

    public void set(K key, V value)
    {
        var node = GetNode(key);
        if (node == null)
        {
            throw new System.Exception(" key:" + key + "   doesn'texisr!");
        }
        else
        {
            node.value = value;
        }
    }
}