69 lines
1.3 KiB
Markdown
69 lines
1.3 KiB
Markdown
---
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title: leetcode-876
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date: 2020-03-26 21:18:41
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tags:
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- leetcode
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categories: leetcode
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---
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### 876. 链表的中间结点
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[题目](https://leetcode-cn.com/problems/middle-of-the-linked-list/)
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<!--more-->
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思路是遍历一遍得到整个链表，讲每个 node 放进一个 list，就可以通过下标得到中间的。
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```python
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# Definition for singly-linked list.
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class ListNode:
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def __init__(self, x):
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self.val = x
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self.next = None
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class Solution:
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def middleNode(self, head: ListNode) -> ListNode:
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l = []
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n = head
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while n.next:
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l.append(n)
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n = n.next
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l.append(n)
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return l[len(l)//2]
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#44 ms 13.7 MB
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```
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看官方解答，还有一个骚操作，通过两个速度不一样的指针，一个一次走一步，一个两次走一步，快的走到底时，慢的就在中间了。
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```python
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class Solution:
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def middleNode(self, head: ListNode) -> ListNode:
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slow = fast = head
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while fast and fast.next:
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slow = slow.next
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fast = fast.next.next
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return slow
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作者：LeetCode-Solution
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链接：https://leetcode-cn.com/problems/middle-of-the-linked-list/solution/lian-biao-de-zhong-jian-jie-dian-by-leetcode-solut/
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来源：力扣（LeetCode）
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著作权归作者所有。商业转载请联系作者获得授权，非商业转载请注明出处。
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```
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