LintCode 删除排序链表中的重复数字 II题目分析代码

/**
 * Definition for ListNode
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) {
 *         val = x;
 *         next = null;
 *     }
 * }
 */
public class Solution {
    /**
     * @param ListNode head is the head of the linked list
     * @return: ListNode head of the linked list
     */
    public static ListNode deleteDuplicates(ListNode head) {
        if(head == null || head.next == null)
            return head;
        
        ListNode dummy = new ListNode(0);
        dummy.next = head;
        head = dummy;

        while (head.next != null && head.next.next != null) {
            if (head.next.val == head.next.next.val) {
                int val = head.next.val;
                while (head.next != null && head.next.val == val) {
                    head.next = head.next.next;
                }            
            } else {
                head = head.next;
            }
        }
        
        return dummy.next;
    }
}