82. Remove Duplicates from Sorted List II(Python3)

82. Remove Duplicates from Sorted List II(Python3)

题目

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.

解题方案

思路：

该题并不复杂，主要是指针的操作，其中要注意的是，最后一个元素如果有多个相同的要进行剔除，这里的处理

代码：

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

class Solution:
def deleteDuplicates(self, head):
"""
:type head: ListNode
:rtype: ListNode
"""
if not head:
return head
tmp = ListNode(0)
tmp.next = head
pre = tmp
front = head
end = head.next
flag = False
while end:
if front.val == end.val:
end = end.next
flag = True
elif flag:
pre.next,front,end = end,end,end.next
flag = False
else:
pre,front,end = front,end,end.next
if flag:
pre.next = None
return tmp.next