数据结构-链表插入

//头节点指针
private Node head;
//尾节点指针
private Node last;
//链表实际长度
private int size;

/**
 * 链表插入元素
 * @param data 插入元素
 * @param index 插入位置
 */
public void insert(int data,int index){
    if (index<0 || index>size){
        throw new IndexOutOfBoundsException("超出链表节点范围");
    }
    Node insertedNode = new Node(data);
    if(size == 0 ){
        //空的链表
        head = insertedNode;
        last = insertedNode;
    } else if (index==0){
        //插头部
        insertedNode.next = head;
        head = insertedNode;
    } else if (index==index){
        //插尾部
        last.next=insertedNode;
        last=insertedNode;
    } else {
        //插中间
        Node prevNode = get(index - 1);
        insertedNode.next = prevNode.next;
        prevNode.next = insertedNode;
    }
    size++;
}

/**
 * 链表删除元素
 * @param index
 * @return
 */
public Node remove(int index){
    if (index < 0 || index>=size){
        throw new IndexOutOfBoundsException("超出链表节点范围");
    }

    Node removedNode = null;
    if (index == 0 ){
        //删除头节点
        removedNode = head;
        head = head.next;
    }else if(index == size-1){
        //删除尾节点
        Node prevNode = get(index-1);
        removedNode = prevNode.next;
        prevNode.next = null;
        last = prevNode;
    } else {
        //删除中间节点
        Node prevNode = get(index-1);
        Node nextNode = prevNode.next.next;
        removedNode = prevNode.next;
        prevNode.next = nextNode;
    }
    size--;
    return removedNode;
}

/**
 * 链表查找元素
 * @param index
 * @return
 */
public Node get(int index ){
    if (index<0 || index>=size){
        throw new IndexOutOfBoundsException("超出链表节点范围");
    }
    Node temp = head;
    for(int i=0; i<index; i++){
        temp = temp.next;
    }
    System.out.println("测试:"+temp);
    return temp;
}

/**
 * 输出链表
 */
public void output(){
    Node temp = head;
    while (temp!=null){
        System.out.println(temp.data);
        temp=temp.next;
    }
}

public static class  Node {
    int data;
    Node next;

    Node(int data) {
        this.data = data;
    }
}

public static void main(String[] args) {
    LinkedList linkedList = new LinkedList();
    linkedList.insert(3,0);
    linkedList.insert(7,1);
    linkedList.insert(9,2);
    linkedList.insert(5,3);
    linkedList.insert(6,1);
    linkedList.remove(0);
    linkedList.output();


}