java - 如何在喜欢列表中任意插入节点？

Question

我即将实现一个能够在链表中任意插入节点的函数。下面的代码适用于在列表的第一个节点插入节点，但对于将节点放在另一个节点后面则不起作用。老实说，我不明白这段代码有什么问题。另外，当我跟踪代码时，我找不到我的错误。请不要禁止我并帮助我解决这个问题。提前致谢。类节点来了:

public class Node {
Object Element;
Node Link;

public Node() {
    this(null,null);
}

public Node(Object Element, Node Link) {
    this.Element = Element;
    this.Link = Link;
}

}

类(class)列表:

 public class List {
Node FirstNode;
Scanner UserInfo = new Scanner(System.in);
Scanner UserInput = new Scanner(System.in);
public List() {
    FirstNode = null;
}
public void InsertArbitrary() {
int Location = UserInput.nextInt(); // Location of new node
if (Location == 1) {
    Object Element = UserInfo.nextLine();
    FirstNode = new Node(Element, FirstNode); // locates a New Node At First
} else {
    Object Element = UserInfo.nextLine(); // Content of new node
    Node CurrentNode ; // for searching in the list 
    CurrentNode = FirstNode;
    for (int i = 1; i <= Location - 1; i++)
        CurrentNode = CurrentNode.Link;
    Node NewNode = new Node (Element , CurrentNode);
}
}
}

Answer 1

迭代到插入位置后，您可以正确创建一个新节点并将其链接分配给下一个元素。但是您没有做的是更新以前的链接以指向新节点，因此列表的尾部不再可以从头节点访问。

你必须做这样的事情(未经测试):

Node FirstNode;
int Length = 0;
public List() {
    FirstNode = null;
}
public void InsertArbitrary(int Location, Object Element) {
    if (Location == 1 || Length == 0) {
        FirstNode = new Node(Element, FirstNode); // locates a New Node At First
        Length++;
    } else {
        Node CurrentNode ; // for searching in the list
        CurrentNode = FirstNode;
        for (int i = 1; i <= Location - 2 && i < Length; i++)
            CurrentNode = CurrentNode.Link;
        Node NewNode = new Node (Element , CurrentNode.Link);
        CurrentNode.Link = NewNode;
        Length++;
    }
}