LinkedList_delDuplication.java

import java.util.*;

public class LinkedList_del_Duplicatation {

    public class ListNode {
        public int val;
        public ListNode next;

        // constructor
        public ListNode(int val) {
            this.val = val;
        }

        // for print
        @Override
        public String toString() {
            return Integer.toString(val);
        }
    }

    //删除单链表中的重复节点
    public static void deleteDuplication(ListNode node) {
        Hashtable table = new Hashtable();
        ListNode previous = null;
        while (node != null) {
            if (table.containsKey(node.val)) {
                previous.next = node.next;
            } else {
                table.put(node.val, true);
                previous = node;
            }
            node = node.next;
        }
    }

    public static void main(String[] args) {
        LinkedList_del_Duplicatation execute = new LinkedList_del_Duplicatation();

        //-构造单链表start----
        int[] num = {1, 2, 2, 3, 4, 5};
        ListNode head = execute.new ListNode(num[0]);
        ListNode pre = head;
        for (int i = 1; i < num.length; i++) {
            ListNode node = execute.new ListNode(num[i]);
            pre.next = node;
            pre = node;
        }

        execute.deleteDuplication(head);

        while (head.next != null) {
            System.out.print(head.val + " ");
            head = head.next;
        }
    }
}