LeetCode--083--删除排序链表中的重复元素

Posted 2020-12-25 Assange

问题描述：

给定一个排序链表，删除所有重复的元素，使得每个元素只出现一次。

示例 1:

输入: 1->1->2
输出: 1->2

示例 2:

输入: 1->1->2->3->3
输出: 1->2->3

 

方法1：（超时）

 1 class Solution(object):
 2     def deleteDuplicates(self, head):
 3         """
 4         :type head: ListNode
 5         :rtype: ListNode
 6         """
 7         
 8         p = head
 9         if p == None or p.next == None:
10             return head
11         while p.next != None:
12             q = p.next
13             if p.val == q.val:
14                 q = q.next
15             else:
16                 p.next = q
17                 p = q
18         return head

方法2:

 1 class Solution(object):
 2     def deleteDuplicates(self, head):
 3         """
 4         :type head: ListNode
 5         :rtype: ListNode
 6         """
 7         
 8         p = head
 9         if p == None or p.next == None:
10             return head
11         while p.next != None:
12             q = p.next
13             if p.val == q.val:
14                 p.next = q.next
15             else:
16                 p = p.next
17         return head

同上：

 1 class Solution(object):
 2     def deleteDuplicates(self, head):
 3         """
 4         :type head: ListNode
 5         :rtype: ListNode
 6         """
 7         #此为不带头结点的链表
 8         if head is None:#链表为空
 9             return head
10         cur=head
11         while cur.next:#下一节点不为空
12             if cur.val==cur.next.val:#第一次判断，头元素与头元素下一节点的值是否相等。。。
13                 cur.next=cur.next.next
14             else:
15                 cur=cur.next
16         return head

方法2：

 1 class Solution(object):
 2     def deleteDuplicates(self, head):
 3         """
 4         :type head: ListNode
 5         :rtype: ListNode
 6         """
 7         a=[]
 8         l=head
 9         while l:
10             if l.val in a:
11                 p.next=l.next
12             else:
13                 a.append(l.val)
14                 p=l
15             l=l.next
16         return head

2018-07-25 13:08:38