手写单链表

public class LinkedList<T> {

    // 节点信息
    class Node {
        T data;
        Node next;

        public Node (T data, Node node){
            this.data = data;
            this.next = node;
        }
    }
    
    Node list; //单链表头部
    int size; //链表有多少个节点

    public LinkedList() {
        size = 0;
    }

    // 添加节点
    // 添加头结点
    public void put(T data){
        Node head = list;
        Node curNode = new Node(data,list);
        list = curNode;
        size++;
    }


    public void put(int index, T data) {
        checkPositionIndex(index);
        Node cur = list;
        Node head = list;
        for (int i = 0; i < index; i++) {
            head = cur;
            cur = cur.next;
        }
        Node = Node(data,cur);
        head.next = node;
        size++;
    }

    // 删除节点
    // 删除头部节点
    public T remove(){
        if(!list) return null;
        Node head = list;
        list = list.next;
        head.next = null; // 促进 GC
        size--;
        return head.data;
    }

    public T remove(int index) {
        checkPositionIndex(index);
        Node cur = list;
        Node head = list;

        for (int i = 0; i < index; i++) {
            head = cur;
            cur = cur.next;
        }

        head.next = cur.next;
        cur.next = null;
        size--;
        return cur.data;
    }

    public T removeLast() {
        
        if(list != null) {
            Node node = list;
            Node cur = list;

            while(cur.next != null) {
                node = cur;
                cur = cur.next;
            }

            node.next = null;
            size --;
            return cur.data;
        }
        return null;
    }
    // 修改节点

    public void set(int index, T newData) {
        checkPositionIndex(index);
        Node head = list;
        for (int i = 0; i < index; i++) {
            head = head.next;
        }
        head.data = newData;
    }

    // 查询节点
    // 头结点
    public T get(){
        
        if(list != null) {
            return list.data;
        }
        return null;
    }

    public T get(int index) {
        checkPositionIndex(index);
        Node head = list;
        for (int i = 0; i < index; i++) {
            head = head.next;
        }
        return head.data;
    }

    private void checkPositionIndex(int index) {
        if(!(index >= 0 && index <= size)) {
            // 抛出错误
        }
    }
}