LeetCode

题目：

Given a sorted linked list, delete all duplicates such that each element appear only once.

For example,
Given 1->1->2, return 1->2.
Given 1->1->2->3->3, return 1->2->3.

思路：

package list;

public class RemoveDuplicatesFromSortedList {

    public ListNode deleteDuplicates(ListNode head) {
        ListNode p = head;
        ListNode start = head;
        while (head != null && head.next != null) {
            ListNode headNext = head.next;
            if (head.next.val != head.val) {
                start = head.next;
            } else {
                start.next = head.next.next;
            }
            
            head = headNext;
        }
        return p;
    }
    
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        ListNode a1 = new ListNode(1);
        ListNode a2 = new ListNode(1);
        ListNode a3 = new ListNode(1);
        ListNode a4 = new ListNode(1);
        ListNode a5 = new ListNode(1);
        a1.next = a2;
        a2.next = a3;
        a3.next = a4;
        a4.next = a5;
        a5.next = null;
        RemoveDuplicatesFromSortedList r = new RemoveDuplicatesFromSortedList();
        ListNode head = r.deleteDuplicates(a1);
        while (head != null) {
            System.out.println(head.val);
            head = head.next;
        }
    }

}