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  • 剑指offer面试题5:逆序打印单链表(Java)

    Java创建单链表(头插法、尾插法),并逆序打印单链表:

    package day_0324;
    import java.util.Scanner;
    import java.util.Stack;
    class ListNode
    {
        int val;
        ListNode next;
        public ListNode(int val)
        {
            this.val=val;
        }
    }
    public class ListNodeTest
    {
        public static void main(String[] args)
        {
            //railInsertCreatList(scanner);
            headInsertCreateList();    
        }
        /**
         * 头插法建立单链表
         * @param scanner
         */
        private static void headInsertCreateList()
        {
            Scanner scanner=new Scanner(System.in);
            while(scanner.hasNext())
            {
                ListNode head=new ListNode(-1);
                head.next=null;//head为头结点,无意义
                String str=scanner.nextLine();
                String[] temp=str.split(" ");
                for(int i=0;i<temp.length;i++)
                {
                    ListNode node=new ListNode(Integer.valueOf(temp[i]));
                    node.next=head.next;
                    head.next=node;
                }
                ListNode p=head.next;
                while(p!=null)
                {
                    System.out.println(p.val);
                    p=p.next;
                }
            }
            scanner.close();
        }
        
        /**
         * 尾插法建立单链表
         * @param scanner
         */
        @SuppressWarnings("unused")
        private static void railInsertCreatList()
        {
            Scanner scanner=new Scanner(System.in);
            while(scanner.hasNext())
            {
                ListNode head=new ListNode(-1);
                head.next=null;
                ListNode r=head;
                String str=scanner.nextLine();
                String[] temp=str.split(" ");
                for(int i=0;i<temp.length;i++)
                {
                    ListNode node=new ListNode(Integer.valueOf(temp[i]));
                    r.next=node;
                    r=node;
                }
                r.next=null;
                ListNode p=head.next;
                while(p!=null)
                {
                    System.out.println(p.val);
                    p=p.next;
                }
            }
            scanner.close();
        }
        /**
         * 递归方法逆序打印单链表
         * @param head
         */
        public static void printListReverse1(ListNode head)
        {
            if(head!=null)
            {
                if(head.next!=null)
                {
                    printListReverse1(head.next);
                }
            }
            System.out.println(head.val);
        }
        /**
         * 使用栈逆序打印单链表
         * @param head
         */
        public static void printListReverse2(ListNode head)
        {
             Stack<Integer> stack=new Stack<Integer>();
            while(head!=null)
            {
                stack.push(head.val);
                head=head.next;     
            }
            while(!stack.isEmpty())
            {
                System.out.println(stack.pop());
            }
        }
    }
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  • 原文地址:https://www.cnblogs.com/xujian2014/p/5314505.html
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