LeetCode，leetcodeoj

LeetCode，leetcodeoj

題目：

Given a sorted linked list, delete all nodes that have duplicate numbers, leaving only distinct numbers from the original list.

For example,
Given 1->2->3->3->4->4->5, return 1->2->5.
Given 1->1->1->2->3, return 2->3.

思路：

package list;public class RemoveDuplicatesFromSortedListII {        public ListNode deleteDuplicates(ListNode head) {        ListNode p = new ListNode(0);        p.next = null;        ListNode prev = p;                ListNode q = head;        while (head != null) {            while (q.next != null && q.next.val == head.val)                q = q.next;            if (q == head) {                prev.next = head;                prev = prev.next;            }                        head = q.next;            q = head;        }                prev.next = null;        return p.next;    }        public static void main(String[] args) {        ListNode a1 = new ListNode(1);        ListNode a2 = new ListNode(2);        ListNode a3 = new ListNode(2);        ListNode a4 = new ListNode(3);        ListNode a5 = new ListNode(4);        a1.next = a2;        a2.next = a3;        a3.next = a4;        a4.next = a5;        a5.next = null;        RemoveDuplicatesFromSortedListII r = new RemoveDuplicatesFromSortedListII();        ListNode head = r.deleteDuplicates(a1);        while (head != null) {            System.out.println(head.val);            head = head.next;        }    }}