鏈表通常由一連串節(jié)點(diǎn)組成，每個(gè)節(jié)點(diǎn)包含任意的實(shí)例數(shù)據(jù)（data fields）和一或兩個(gè)用來(lái)指向上一個(gè)/或下一個(gè)節(jié)點(diǎn)的位置的鏈接（"links"）

package com.ys.datastructure;
public class SingleLinkedList {
    private int size;//鏈表節(jié)點(diǎn)的個(gè)數(shù)
    private Node head;//頭節(jié)點(diǎn)
    public SingleLinkedList(){
        size = 0;
        head = null;
    }
    //鏈表的每個(gè)節(jié)點(diǎn)類(lèi)
    private class Node{
        private Object data;//每個(gè)節(jié)點(diǎn)的數(shù)據(jù)
        private Node next;//每個(gè)節(jié)點(diǎn)指向下一個(gè)節(jié)點(diǎn)的連接
        public Node(Object data){
            this.data = data;
        }
    }
    //在鏈表頭添加元素
    public Object addHead(Object obj){
        Node newHead = new Node(obj);
        if(size == 0){
            head = newHead;
        }else{
            newHead.next = head;
            head = newHead;
        }
        size++;
        return obj;
    }
    //在鏈表頭刪除元素
    public Object deleteHead(){
        Object obj = head.data;
        head = head.next;
        size--;
        return obj;
    }
    //查找指定元素，找到了返回節(jié)點(diǎn)Node，找不到返回null
    public Node find(Object obj){
        Node current = head;
        int tempSize = size;
        while(tempSize > 0){
            if(obj.equals(current.data)){
                return current;
            }else{
                current = current.next;
            }
            tempSize--;
        }
        return null;
    }
    //刪除指定的元素，刪除成功返回true
    public boolean delete(Object value){
        if(size == 0){
            return false;
        }
        Node current = head;
        Node previous = head;
        while(current.data != value){
            if(current.next == null){
                return false;
            }else{
                previous = current;
                current = current.next;
            }
        }
        //如果刪除的節(jié)點(diǎn)是第一個(gè)節(jié)點(diǎn)
        if(current == head){
            head = current.next;
            size--;
        }else{//刪除的節(jié)點(diǎn)不是第一個(gè)節(jié)點(diǎn)
            previous.next = current.next;
            size--;
        }
        return true;
    }
    //判斷鏈表是否為空
    public boolean isEmpty(){
        return (size == 0);
    }
    //顯示節(jié)點(diǎn)信息
    public void display(){
        if(size >0){
            Node node = head;
            int tempSize = size;
            if(tempSize == 1){//當(dāng)前鏈表只有一個(gè)節(jié)點(diǎn)
                System.out.println("["+node.data+"]");
                return;
            }
            while(tempSize>0){
                if(node.equals(head)){
                    System.out.print("["+node.data+"->");
                }else if(node.next == null){
                    System.out.print(node.data+"]");
                }else{
                    System.out.print(node.data+"->");
                }
                node = node.next;
                tempSize--;
            }
            System.out.println();
        }else{//如果鏈表一個(gè)節(jié)點(diǎn)都沒(méi)有，直接打印[]
            System.out.println("[]");
        }
    }
}

@Test
public void testSingleLinkedList(){
    SingleLinkedList singleList = new SingleLinkedList();
    singleList.addHead("A");
    singleList.addHead("B");
    singleList.addHead("C");
    singleList.addHead("D");
    //打印當(dāng)前鏈表信息
    singleList.display();
    //刪除C
    singleList.delete("C");
    singleList.display();
    //查找B
    System.out.println(singleList.find("B"));
}

package com.ys.datastructure;
public class StackSingleLink {
    private SingleLinkedList link;
    public StackSingleLink(){
        link = new SingleLinkedList();
    }
    //添加元素
    public void push(Object obj){
        link.addHead(obj);
    }
    //移除棧頂元素
    public Object pop(){
        Object obj = link.deleteHead();
        return obj;
    }
    //判斷是否為空
    public boolean isEmpty(){
        return link.isEmpty();
    }
    //打印棧內(nèi)元素信息
    public void display(){
        link.display();
    }
}

package com.ys.link;
public class DoublePointLinkedList {
    private Node head;//頭節(jié)點(diǎn)
    private Node tail;//尾節(jié)點(diǎn)
    private int size;//節(jié)點(diǎn)的個(gè)數(shù)
    private class Node{
        private Object data;
        private Node next;
        public Node(Object data){
            this.data = data;
        }
    }
    public DoublePointLinkedList(){
        size = 0;
        head = null;
        tail = null;
    }
    //鏈表頭新增節(jié)點(diǎn)
    public void addHead(Object data){
        Node node = new Node(data);
        if(size == 0){//如果鏈表為空，那么頭節(jié)點(diǎn)和尾節(jié)點(diǎn)都是該新增節(jié)點(diǎn)
            head = node;
            tail = node;
            size++;
        }else{
            node.next = head;
            head = node;
            size++;
        }
    }
    //鏈表尾新增節(jié)點(diǎn)
    public void addTail(Object data){
        Node node = new Node(data);
        if(size == 0){//如果鏈表為空，那么頭節(jié)點(diǎn)和尾節(jié)點(diǎn)都是該新增節(jié)點(diǎn)
            head = node;
            tail = node;
            size++;
        }else{
            tail.next = node;
            tail = node;
            size++;
        }
    }
    //刪除頭部節(jié)點(diǎn)，成功返回true，失敗返回false
    public boolean deleteHead(){
        if(size == 0){//當(dāng)前鏈表節(jié)點(diǎn)數(shù)為0
            return false;
        }
        if(head.next == null){//當(dāng)前鏈表節(jié)點(diǎn)數(shù)為1
            head = null;
            tail = null;
        }else{
            head = head.next;
        }
        size--;
        return true;
    }
    //判斷是否為空
    public boolean isEmpty(){
        return (size ==0);
    }
    //獲得鏈表的節(jié)點(diǎn)個(gè)數(shù)
    public int getSize(){
        return size;
    }
    //顯示節(jié)點(diǎn)信息
    public void display(){
        if(size >0){
            Node node = head;
            int tempSize = size;
            if(tempSize == 1){//當(dāng)前鏈表只有一個(gè)節(jié)點(diǎn)
                System.out.println("["+node.data+"]");
                return;
            }
            while(tempSize>0){
                if(node.equals(head)){
                    System.out.print("["+node.data+"->");
                }else if(node.next == null){
                    System.out.print(node.data+"]");
                }else{
                    System.out.print(node.data+"->");
                }
                node = node.next;
                tempSize--;
            }
            System.out.println();
        }else{//如果鏈表一個(gè)節(jié)點(diǎn)都沒(méi)有，直接打印[]
            System.out.println("[]");
        }
    }
}

package com.ys.link;
public class QueueLinkedList {
    private DoublePointLinkedList dp;
    public QueueLinkedList(){
        dp = new DoublePointLinkedList();
    }
    public void insert(Object data){
        dp.addTail(data);
    }
    public void delete(){
        dp.deleteHead();
    }
    public boolean isEmpty(){
        return dp.isEmpty();
    }
    public int getSize(){
        return dp.getSize();
    }
    public void display(){
        dp.display();
    }
}

package com.ys.datastructure;
public class OrderLinkedList {
    private Node head;
    private class Node{
        private int data;
        private Node next;
        public Node(int data){
            this.data = data;
        }
    }
    public OrderLinkedList(){
        head = null;
    }
    //插入節(jié)點(diǎn)，并按照從小打到的順序排列
    public void insert(int value){
        Node node = new Node(value);
        Node pre = null;
        Node current = head;
        while(current != null && value > current.data){
            pre = current;
            current = current.next;
        }
        if(pre == null){
            head = node;
            head.next = current;
        }else{
            pre.next = node;
            node.next = current;
        }
    }
    //刪除頭節(jié)點(diǎn)
    public void deleteHead(){
        head = head.next;
    }
    public void display(){
        Node current = head;
        while(current != null){
            System.out.print(current.data+" ");
            current = current.next;
        }
        System.out.println("");
    }
}

package com.ys.datastructure;
public class TwoWayLinkedList {
    private Node head;//表示鏈表頭
    private Node tail;//表示鏈表尾
    private int size;//表示鏈表的節(jié)點(diǎn)個(gè)數(shù)
    private class Node{
        private Object data;
        private Node next;
        private Node prev;
        public Node(Object data){
            this.data = data;
        }
    }
    public TwoWayLinkedList(){
        size = 0;
        head = null;
        tail = null;
    }
    //在鏈表頭增加節(jié)點(diǎn)
    public void addHead(Object value){
        Node newNode = new Node(value);
        if(size == 0){
            head = newNode;
            tail = newNode;
            size++;
        }else{
            head.prev = newNode;
            newNode.next = head;
            head = newNode;
            size++;
        }
    }
    //在鏈表尾增加節(jié)點(diǎn)
    public void addTail(Object value){
        Node newNode = new Node(value);
        if(size == 0){
            head = newNode;
            tail = newNode;
            size++;
        }else{
            newNode.prev = tail;
            tail.next = newNode;
            tail = newNode;
            size++;
        }
    }
    //刪除鏈表頭
    public Node deleteHead(){
        Node temp = head;
        if(size != 0){
            head = head.next;
            head.prev = null;
            size--;
        }
        return temp;
    }
    //刪除鏈表尾
    public Node deleteTail(){
        Node temp = tail;
        if(size != 0){
            tail = tail.prev;
            tail.next = null;
            size--;
        }
        return temp;
    }
    //獲得鏈表的節(jié)點(diǎn)個(gè)數(shù)
    public int getSize(){
        return size;
    }
    //判斷鏈表是否為空
    public boolean isEmpty(){
        return (size == 0);
    }
    //顯示節(jié)點(diǎn)信息
    public void display(){
        if(size >0){
            Node node = head;
            int tempSize = size;
            if(tempSize == 1){//當(dāng)前鏈表只有一個(gè)節(jié)點(diǎn)
                System.out.println("["+node.data+"]");
                return;
            }
            while(tempSize>0){
                if(node.equals(head)){
                    System.out.print("["+node.data+"->");
                }else if(node.next == null){
                    System.out.print(node.data+"]");
                }else{
                    System.out.print(node.data+"->");
                }
                node = node.next;
                tempSize--;
            }
            System.out.println();
        }else{//如果鏈表一個(gè)節(jié)點(diǎn)都沒(méi)有，直接打印[]
            System.out.println("[]");
        }
    }
}