LeetCode解題分享：82. Remove Duplicates from Sorted List II

Problem

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

Example 1:

Input: 1->2->3->3->4->4->5
Output: 1->2->5

Example 2:

Input: 1->1->1->2->3
Output: 2->3

解題思路

   這一題的總體思路就是從頭開始遍歷，遇見相同的刪除就好。

   代碼如下：

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


class Solution:
    def deleteDuplicates(self, head: ListNode) -> ListNode:
        H = ListNode(- float("inf"))
        H.next = head
        tail = H
        while head:
            if head.next and head.val == head.next.val:
                current = head.val
                while head and head.val == current:
                    tail.next = head.next
                    head = head.next
            else:
                tail = head
                head = head.next

        return H.next