leetcode 83. Remove Duplicates from Sorted List

Given a sorted linked list, delete all duplicates such that each element appear only once.

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

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# 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         """         node = head         while node:             tmp = node             val = node.val                        while node.next and node.next.val == val:                 node = node.next             # assert node.next is None or node.next.val != val             tmp.next = node.next             node = node.next         return head

 

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# 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         """         dummy = cur = ListNode(None)         node = head         while node:             if node.val != cur.val:                 cur.next = node                 cur = cur.next             node = node.next         cur.next = None         return dummy.next

 

发现其他人的解法和我的都不一样，每次上一个节点比较，如果数值相同，则直接删除当前节点。

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# 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         """         if not head: return None              node = head         while node.next:             if node.next.val == node.val:                 node.next = node.next.next             else:                 node = node.next         return head

 递归解法：

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# 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         """         if not head: return None                      if not head.next: return head                head.next = self.deleteDuplicates(head.next)         if head.val == head.next.val:             return head.next         else:             return head