delete-the-middle-node-of-a-linked-list

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Algorithms

You are given the <code>head</code> of a linked list. Delete the middle node, and return the <code>head</code> of the modified linked list.

The middle node of a linked list of size <code>n</code> is the <code>&lfloor;n / 2&rfloor;th</code> node from the start using 0-based indexing, where <code>&lfloor;x&rfloor;</code> denotes the largest integer less than or equal to <code>x</code>.

<ul>
	<li>For <code>n</code> = <code>1</code>, <code>2</code>, <code>3</code>, <code>4</code>, and <code>5</code>, the middle nodes are <code>0</code>, <code>1</code>, <code>1</code>, <code>2</code>, and <code>2</code>, respectively.</li>
</ul>

&nbsp;
Example 1:
<img alt="" src="https://assets.leetcode.com/uploads/2021/11/16/eg1drawio.png" style="width: 500px; height: 77px;" />
<pre>
Input: head = [1,3,4,7,1,2,6]
Output: [1,3,4,1,2,6]
Explanation:
The above figure represents the given linked list. The indices of the nodes are written below.
Since n = 7, node 3 with value 7 is the middle node, which is marked in red.
We return the new list after removing this node. 
</pre>

Example 2:
<img alt="" src="https://assets.leetcode.com/uploads/2021/11/16/eg2drawio.png" style="width: 250px; height: 43px;" />
<pre>
Input: head = [1,2,3,4]
Output: [1,2,4]
Explanation:
The above figure represents the given linked list.
For n = 4, node 2 with value 3 is the middle node, which is marked in red.
</pre>

Example 3:
<img alt="" src="https://assets.leetcode.com/uploads/2021/11/16/eg3drawio.png" style="width: 150px; height: 58px;" />
<pre>
Input: head = [2,1]
Output: [2]
Explanation:
The above figure represents the given linked list.
For n = 2, node 1 with value 1 is the middle node, which is marked in red.
Node 0 with value 2 is the only node remaining after removing node 1.</pre>

&nbsp;
Constraints:

<ul>
	<li>The number of nodes in the list is in the range <code>[1, 105]</code>.</li>
	<li><code>1 &lt;= Node.val &lt;= 105</code></li>
</ul>

deleteMiddle

Delete the Middle Node of a Linked List

Remove Nth Node From End of List

remove-nth-node-from-end-of-list

删除链表的倒数第 N 个结点

Reorder List

reorder-list

重排链表

Remove Linked List Elements

remove-linked-list-elements

移除链表元素

Middle of the Linked List

middle-of-the-linked-list

链表的中间结点

Linked List

Two Pointers

给你一个链表的头节点 <code>head</code> 。删除 链表的 中间节点 ，并返回修改后的链表的头节点 <code>head</code> 。

长度为 <code>n</code> 链表的中间节点是从头数起第 <code>⌊n / 2⌋</code> 个节点（下标从 0 开始），其中 <code>⌊x⌋</code> 表示小于或等于 <code>x</code> 的最大整数。

<ul>
	<li>对于 <code>n</code> = <code>1</code>、<code>2</code>、<code>3</code>、<code>4</code> 和 <code>5</code> 的情况，中间节点的下标分别是 <code>0</code>、<code>1</code>、<code>1</code>、<code>2</code> 和 <code>2</code> 。</li>
</ul>

&nbsp;

示例 1：

<img alt="" src="https://assets.leetcode.com/uploads/2021/11/16/eg1drawio.png" style="width: 500px; height: 77px;" />

<pre>
输入：head = [1,3,4,7,1,2,6]
输出：[1,3,4,1,2,6]
解释：
上图表示给出的链表。节点的下标分别标注在每个节点的下方。
由于 n = 7 ，值为 7 的节点 3 是中间节点，用红色标注。
返回结果为移除节点后的新链表。 
</pre>

示例 2：

<img alt="" src="https://assets.leetcode.com/uploads/2021/11/16/eg2drawio.png" style="width: 250px; height: 43px;" />

<pre>
输入：head = [1,2,3,4]
输出：[1,2,4]
解释：
上图表示给出的链表。
对于 n = 4 ，值为 3 的节点 2 是中间节点，用红色标注。
</pre>

示例 3：

<img alt="" src="https://assets.leetcode.com/uploads/2021/11/16/eg3drawio.png" style="width: 150px; height: 58px;" />

<pre>
输入：head = [2,1]
输出：[2]
解释：
上图表示给出的链表。
对于 n = 2 ，值为 1 的节点 1 是中间节点，用红色标注。
值为 2 的节点 0 是移除节点 1 后剩下的唯一一个节点。</pre>

&nbsp;

提示：

<ul>
	<li>链表中节点的数目在范围 <code>[1, 105]</code> 内</li>
	<li><code>1 &lt;= Node.val &lt;= 105</code></li>
</ul>