LeetCode 82 [Remove Duplicates from Sorted List II]

原题

给定一个排序链表，删除所有重复的元素只留下原链表中没有重复的元素。

样例
给出 1->2->3->3->4->4->5->null，返回 1->2->5->null
给出 1->1->1->2->3->null，返回 2->3->null

解题思路

• 基础链表操作，与Remove Duplicates from Sorted List I的区别是如果有重复，重复的节点全部删除
• 因为头节点有被删除的可能，所以使用dummy node

完整代码

# Definition for singly-linked list.
# class ListNode(object):
#     def __init__(self, x):
#         self.val = x
#         self.next = None

class Solution(object):
    def deleteDuplicates(self, head):
        """
        :type head: ListNode
        :rtype: ListNode
        """
        DummyNode = ListNode(0)
        DummyNode.next = head
        
        current = DummyNode
        while current.next != None and current.next.next != None:
            if current.next.val == current.next.next.val:
                temp = current.next.val
                while current.next != None and current.next.val == temp:
                    current.next = current.next.next
            else:
                current = current.next
                
        return DummyNode.next