從鏈表中刪除一個元素

Question

如何從鏈表中刪除一個元素？

是否正確：

public E remove(E element) {
        Node search = currentNode;
        boolean nonStop = true;
        while(((search.previous) != null) && (nonStop)) {
            if(search.previous.toString().equals(element.toString())) {
                System.out.println("Item found !!!");
                search.previous = search.previous.previous;
                nonStop = false;
            } else {
                search = search.previous;
            }
        }
        currentNode = search;
        return null;
    }

public class Node<E> {
    public E data;
    public Node<E> previous;

    public Node(E data) {
        this.data = data;
    }

    public void printNode() {
        System.out.println("Node details: "+data);
    }

    @Override
    public String toString() {
        // TODO Auto-generated method stub
        return (String)data;
    }

}

問題是當我打印所有元素時，getAllElements（）沒有給出正確答案，remove（）方法或getAllElements中是否有任何問題

public void getAllElements() {
        Node<E> aNode = currentNode;
        while(aNode != null) {
            aNode.printNode();
            aNode = aNode.previous;
        }
    }

Answer 1

線

if(search.previous.toString().equals(element.toString())

調用節點上而不是元素上的字符串。

Answer 2

看來您的remove方法實際上並沒有刪除任何內容，您應該更新方法中的指針，以使任何內容都指向您要刪除的元素，然后垃圾回收器將刪除所有未指向的元素。 一些偽代碼來說明我的意思：

public remove(Element element){
  for (Element e : myLinkedList){
    if (e.equals(element)){
      if (next != 0)
        previousPtr = nextPtr;
      else
        previousPtr = null;
    }
  }
}

注意這不是正確的Java代碼，只是偽代碼給您一個想法，我為您節省了一些樂趣！ :)

Answer 3

嘗試這個：

public void remove(E element)
{
    Node n = head;  // This is the head of the linked list-- It is the starting node of your linked list: For your case "currentNode"
    Node tmp;
    while(n!=null && !n.data.equals(element))
    {
        tmp = n;
        n = n.previous;
    }

    if(n==null)
    {
        // Do your stuff
        System.out.println("Element "+element+" not found.");
    }
    else
    {
        // Do your stuff
        tmp.prev = n.prev;
        n.prev = null;
        System.out.println("Element "+element+" removed.");
    }
}


// Suggestion: This method name should be "printList()"
public void getAllElements()
{
    Node n = head;      // In your case: "currentNode"
    while(n!=null)
    {
        n.printNode();
        n = n.previous;
    }   
}

Answer 4

您的元素沒有某種標識符嗎？ 然后，您可以將其簡單得多，例如： 刪除對象

Answer 5

public E remove(E element) {
        Node search = currentNode;
        boolean nonStop = true;
        while(((search.previous) != null) && (nonStop)) {
            if(search.previous.data.equals(element)) {
                System.out.println("Item found !!!");
                search.previous = search.previous.previous;
                nonStop = false;
            }
            search = search.previous;
        }
       return null;
    }

我已經找到了該問題的解決方案，感謝大家的支持。