我试图从通用链表中删除一个节点,而不是删除整个列表。我希望它删除一个类似的项目。我试图找到这样做的正确方法。我还需要它去最后一个节点,准备在删除节点后添加节点。
import java.util.Scanner;
import java.io.*;
class MyGenericList <T extends Comparable<T> >
{
private class Node<B>
{
T value;
Node<T> next;
}
private Node<T> first = null;
int count = 0;
public void add(T element)
{
Node<T> newnode = new Node<T>();
newnode.value = element;
newnode.next = null;
if (first == null)
{
first = newnode;
}
else
{
Node<T> lastnode = gotolastnode(first);
lastnode.next = newnode;
}
count++;
}
public void remove(T element)
{
Node<T> newnode = new Node<T>();
Node<T> prevnode = new Node<T>();
Node<T> curnode = new Node<T>();
prevnode.value = element;
curnode.next = null;
int hopcount=0;
while(hopcount < count)
{
if(prevnode == element)
{
prevnode.next = first;
Node<T> lastnode = gotolastnode(first);
lastnode.next = newnode;
}
hopcount++;
}
count--;
}
public T get(int pos)
{
Node<T> Nodeptr = first;
int hopcount=0;
while (hopcount < count && hopcount<pos)
{ if(Nodeptr != null)
{
Nodeptr = Nodeptr.next;
}
hopcount++;
}
return Nodeptr.value;
}
private Node<T> gotolastnode(Node<T> nodepointer)
{
if (nodepointer== null )
{
return nodepointer;
}
else
{
if (nodepointer.next == null)
return nodepointer;
else
return gotolastnode( nodepointer.next);
}
}
}
class Employee implements Comparable<Employee>
{
String name;
int age;
@Override
public int compareTo(Employee arg0)
{
// TODO Auto-generated method stub
return 0;
// implement compareto method here.
}
Employee( String nm, int a)
{
name =nm;
age = a;
}
}
class City implements Comparable<City>
{
String name;
int population;
City( String nm, int p)
{
name =nm;
population = p;
}
@Override
public int compareTo(City arg0) {
// TODO Auto-generated method stub
return 0;
// implement compareto method here.
}
}
public class GenericLinkedList
{
public static void main(String[] args) throws IOException
{
MyGenericList<Employee> ml = new MyGenericList<>();
ml.add(new Employee("john", 32));
ml.add(new Employee("susan", 23));
ml.add(new Employee("dale", 45));
ml.add(new Employee("eric", 23));
Employee e1 = ml.get(0);
System.out.println( "Name " + e1.name + " Age "+ e1.age );
ml.remove(new Employee("john", 32));
System.out.println( "Name " + e1.name + " Age "+ e1.age );
ml.add(new Employee("john", 32));
System.out.println( "Name " + e1.name + " Age "+ e1.age );
MyGenericList<City> citylist = new MyGenericList<>();
citylist.add(new City("Los Angeles", 320000));
citylist.add(new City("Santa monica", 230000));
citylist.add(new City("San Francisco", 450000));
citylist.add(new City("San Diego", 23000));
City c= citylist.get(2);
System.out.println( "City " + c.name + " Population "+ c.population );
}
}
我没有删除整个列表,而是删除了一个。
使用数据结构时,在尝试编写代码之前使用实际图表可能特别有用。我们来看看:
我们可以看到,我们只需将prev指向cur之外的节点(我们需要删除的节点)。步骤如下:
1)声明两个节点,第一个指向第一个(prev),第二个指向prev之后的节点。
2)使用while循环将cur和prev增加到正确的位置(cur应该指向要删除的节点)。
3)用一行代码删除节点(prev.next = cur.next)。
4)减少计数,你就完成了。
(如果你需要为addLast操作定位,只需将cur移动到最后一个节点,即cur = cur.next,而cur.next!= null)。
按值删除的完整代码如下:
public void remove(T element){
Node<T> cur = first.next;
Node<T> prev = first;
Node<T> nn = new Node(element);//I'm assuming you have constructors that accept data
boolean deleted = false;
while(cur!=null&&deleted == false){
if(cur.data.equals(element)){
prev.next = cur.next;
this.count--;
deleted = true;
}
}
prev = gotolastnode(prev);
prev.next = nn;
}
这应该根据您的方法签名进行删除。但是,您可能必须更改gotolastnode方法才能使其正常工作。