如何在Java链表中指定索引处插入对象

Question

尝试在链表java类的指定索引处插入对象。我不太确定如何实现这个。

下面是一个方法参数的例子，以及我到目前为止所拥有的(不工作):

  void insertAtIndex(int idx, Shape data){
    if (idx == 0) {
        //insert the new Shape at the beginning of the list
        insertAtBeginning(data);
    }else{
        Node temp = head;
        for(int i = 0; i < idx - 1; i++)
            temp = temp.getNext();
        Node next = new Node(data);
        next = temp.getNext();
        temp = next;
    }
}

Node的子类:

public Node(Shape data){
    //Make next point to null
    next = null;
    this.data = data;
}
// another Node constructor if we want to specify the node to point to.
public Node(Shape dataVal, Node nextVal){
    next = nextVal;
    data = dataVal;
}
//Getter for data
public Shape getData(){
    return data;
}
//Setter for data
public void setData(Shape data){
    this.data = data;
}
//Getter for next
public Node getNext() {
    return next;
}
//Setter for next
public void setNext(Node next) {
    this.next = next;
}

链表类:

public class ShapeLinkedList {
public Node head; //head is first node in linked list
public Node tail; //tail is last node in linked list
public ShapeLinkedList(){}
public ShapeLinkedList(Node head){
    head = null;
    tail = null;
}
public boolean isEmpty(){
    return length() == 0;
}

Answer 1

就用LinkedList#add(int index, E element):

public void add(int index, E element)

将指定元素插入此列表中的指定位置。移动当前在该位置的元素(如果有的话)和右边的任何后续元素(在它们的指数)。

Answer 2

开头不错:D

现在你需要这样看……

a -> b -> c -> d

如果你想在索引0处添加…

e -> a ->…对吧?

如果你的索引是1，那么…

a-> e -> b -> c -> d

也就是说，索引项AT指向新形状，新形状指向原来在索引2中的下一个项(但AFTER将是索引3)