用结点实现链表LinkedList，用数组和结点实现栈Stack，用数组和结点链表实现队列Queue

一，用结点实现链表LinkedList，不用换JavaAPI的集合框架

import java.util.Scanner;public class Main {    public static class Node {    int data;    Node next=null;    public Node(int data){this.data=data;};    }    public static class MyLinkedList {    Node head=null;        public MyLinkedList() {}        //添加节点public void addNode(int d){    Node newNode=new Node(d);    if(head==null){    head=newNode;    return ;    }     Node tmp=head;     while(tmp.next!=null){//找到结尾     tmp=tmp.next;     }    tmp.next=newNode;       }//链表长度public int size(Node head){int count=0;Node tmp=head;while(tmp.next!=null){count++;tmp=tmp.next;}return count+1;}//删除节点public boolean deleteNode(int d){if(head.data==d){head=head.next;return true;}Node preNode=head;Node curNode=head.next;while(curNode!=null){if(curNode.data==d){preNode.next=curNode.next;return true;}preNode=curNode;curNode=curNode.next;}return false;}//对链表进行排序,返回排序后的头结点public Node orderList(){Node nextNode=null;int temp=0;Node curNode=head;while(curNode.next!=null){nextNode=curNode.next;while(nextNode!=null){if(curNode.data>nextNode.data){//只交换数据temp = curNode.data;curNode.data=nextNode.data;nextNode.data=temp;}nextNode=nextNode.next;}curNode=curNode.next;}//选择排序算法/*while(curNode.next!=null){nextNode=curNode.next;Node k=curNode;int tmp=curNode.data;while(nextNode!=null){if(nextNode.data<tmp){ tmp=nextNode.data; k=nextNode;}nextNode=nextNode.next;}if(k!=curNode){int t=k.data;k.data=curNode.data;curNode.data=t;}curNode=curNode.next;}*/return head;}//打印链表public void printList(){Node tmp=head;{while(tmp!=null){System.out.print(tmp.data+" ");tmp=tmp.next;}}}    }    public static void main(String[] args) { Scanner in=new Scanner(System.in); int n=in.nextInt(); int[] nodes=new int[n]; for(int i=0;i<n;i++){ nodes[i]=in.nextInt(); }         int k=in.nextInt();         MyLinkedList list=new MyLinkedList();         for(int i=0;i<n;i++){         list.addNode(nodes[i]); }         //LinkedList list2=new LinkedList();                  Node p=FindKthToTail(list.head,k);         System.out.println(p.data);}//单链表找到倒数第k个数public static Node FindKthToTail(Node head,int k){if(k<=0||head==null){return null;}Node p1=head;Node p2=head;for(int i=0;i<k+1;i++){//先走k步p1=p1.next;}while(p1!=null){p1=p1.next;p2=p2.next;}return p2;}}

二，实现栈Stack

1，使用一般的数组Object[]实现栈

import java.util.Arrays;public class Main {  public static class MyStack<E>{  private Object[] stack;//用数组实现栈  private int size;//数组的大小  public MyStack(){  stack=new Object[10];  }  public boolean isEmpty(){  return size==0;  }    public E peek(){  if(isEmpty()){  return null;  }  return (E) stack[size-1];    }    public E pop(){   E e=peek();   stack[size-1]=null;   size--;   return e;    }  public boolean push(E item){  ensureCapacity(size+1);  stack[size++]=item;  return true;  }    private void ensureCapacity(int size){  int len=stack.length;  if(len<size){  int newLen=10;  stack=Arrays.copyOf(stack, newLen);    }  }    }public static void main(String[] args) {  MyStack<Integer> s=new MyStack<Integer>();  s.push(52);  s.push(20);  s.push(96);  System.out.println("栈中元素个数："+s.size);  System.out.println("栈顶元素："+s.pop());  System.out.println("栈顶元素："+s.pop());  }}

2,使用结点链表实现栈，这是一直在链表头插入，向左扩展。让我们先忽略JavaAPI提供的集合框架，咱主要讨论的是思想

public class Main {//节点类    public static class Node<E>{    E data;    Node<E> next=null;public Node(E data) {this.data = data;}            }        public static class MyStack<E>{    Node<E> top=null;//相当于链表头          public boolean push(E d){    Node<E> newNode=new Node<E>(d);    if(top!=null){    newNode.next=top;//一直在链表头插入，想左扩展    }    top=newNode;    return true;    }    public E peek(){    if(top==null)    return null;    return top.data;    }    public E pop(){    E e=peek();    top=top.next;    return e;    }    public boolean isEmpty(){    return top==null;    }    public int size(){    if(isEmpty()){    return 0;    }    Node<E> tmp=top;        int size=0;    while(tmp!=null){    size++;    tmp=tmp.next;    }    return size;    }            }public static void main(String[] args) {  MyStack<Integer> s=new MyStack<Integer>();  s.push(52);  s.push(20);  s.push(96);  System.out.println("栈中元素个数："+s.size());  System.out.println("栈顶元素："+s.pop());  System.out.println("栈顶元素："+s.pop());}}

三，实现队列Queue

1，用数组实现队列，这时用集合框架LinkedList是最好的方法

import java.util.ArrayList;import java.util.LinkedList;public class Main {    public static class MyQueue<E>{    private LinkedList<E> queue;//用的是Api的集合框架，为什么要用LinkedList。因为LinkedList有addlast和addFirst方法,可以在两端任意操作，使用ArrayList就比较麻烦    private int size=0;    public MyQueue(){    queue=new LinkedList<E>();    }        public boolean Enqueue(E e){    queue.addLast(e);    size++;    return true;    }    public E Dequeue(){    size--;    return queue.removeFirst();    }    public boolean Empty(){    return size==0;    }    public int size(){        return queue.size();    }        public void printQueue(){    System.out.println(queue.toString());    }        }public static void main(String[] args) {  MyQueue<Integer> q=new MyQueue<Integer>();  q.Enqueue(52);  q.Enqueue(42);  q.Enqueue(71);  q.Enqueue(23);  q.printQueue();  q.Dequeue();  q.printQueue();  q.Dequeue();  q.printQueue();  q.Dequeue();  q.printQueue();  /*   * [52, 42, 71, 23] [42, 71, 23] [71, 23] [23]   *    * */     }}

2，用结点链表实现队列。

public class Main {public static class Node<E>{E data;Node<E> next=null;public Node(E data){this.data=data;}}public static class MyQueue<E>{Node<E> head=null,tail=null;public boolean Enqueue(E e){Node<E> newNode=new Node<E>(e);if(head==null&&tail==null){head=newNode;tail=newNode;}tail.next=newNode;tail=newNode;return true;}public E Dequeue(){if(head==null){return null;}E e=head.data;head=head.next;return e;}public boolean isEmpty(){return head==tail;}public int size(){Node<E> tmp=head;int count=0;while(tmp!=null){count++;tmp=tmp.next;}return count;}public void printQueue(){Node<E> tmp=head;while(tmp!=null){System.out.print(tmp.data+" ");tmp=tmp.next;}System.out.println();    }}public static void main(String[] args) {// TODO Auto-generated method stub MyQueue<Integer> q=new MyQueue<Integer>();  q.Enqueue(52);  q.Enqueue(42);  q.Enqueue(71);  q.Enqueue(23);  q.printQueue();  q.Dequeue();  q.printQueue();  q.Dequeue();  q.printQueue();  q.Dequeue();  q.printQueue();/*52 42 71 23 <span style="white-space:pre"></span> *42 71 23 <span style="white-space:pre"></span> *71 23                  *23 */}}