Question

我的方法int deletLast（）应该删除最后一个节点，并返回被删除节点内的值。我的代码似乎不起作用。它不会删除最后一个节点。任何帮助将不胜感激。

import java.util.NoSuchElementException; import java.util.Scanner;

公共类LinkedList11 { //私有内部类节点

private class Node{
    int data;
    Node link;


    public Node(){
        data = Integer.MIN_VALUE;
        link = null;
    }

    public Node(int x, Node p){
        data = x;
        link = p;
    }
}
// End of Node class

public Node head;

public LinkedList11(){
    head = null;
}

public int deleteLast() throws NoSuchElementException {


    if ( head == null )   //handle when list is empty
    { throw new NoSuchElementException();}

     if(head.link == null)  //handle when head is the only node
     { return head.data;


        }

        Node position = head;
        Node temp = head;   //temp has to be initialized to something 
        int dataAtEnd =0;
        while (position != null)
        {   dataAtEnd = position.data;    
            temp =position;               //safe keep current position
           position = position.link;     //update position pointer to get the next value  
          }

       position =temp;  // store current position in next position
       return dataAtEnd;

}

}

Answer 1

首先，如果head是唯一的节点并且你想删除它，你需要设置head null。

if(head.link == null) {
    int result = head .data;
    head = null;
    return result;
}

在检查head是否是唯一节点后尝试这样的事情：

Node current = head;
while (current.link.link != null)
    current = current.link;
int result = current.link.data;
current.link = null;
return result;

Bc你需要查看前面的步骤，检查下一个节点是否是最后一个节点，并从最后一个节点之前删除最后一个节点。我希望你明白，我的意思和抱歉打字错误

Answer 2

删除行＆＃34;返回head.data;＆＃34;就在您收到错误的地方正上方。＆＃34; ead = null; //给出错误＆＃34;因为你上面有一个返回语句，因此显然无法访问

，因此无法访问

`public int deleteLast（）抛出NoSuchElementException {

if ( head == null )   //handle when list is empty
{ throw new NoSuchElementException();}

 if(head.link == null)  //handle when head is the only node
 { 
     // You must store the data somewhere since head has to be set to NULL.
     int dataToReturn = head.data;

     // Since head is the only node, set it to NULL now.
     head = null;

     // Now return the data the the last node (head in this case) contained.
     return dataToReturn;
    }

    Node position = head;
    Node temp = head;   //temp has to be initialized to something 
    int dataAtEnd =0;

    while (position.link != null)
    {   dataAtEnd = position.data;    
        temp =position;               //safe keep current position
       position = position.link;     //update position pointer to get the next value  
      }

   position = null;
   temp.link = null;//this is what deletes the last node.

   return dataAtEnd;

}

从单链表中删除最后一个节点（java）

2 个答案: