mirror of
https://gitee.com/coder-xiaomo/leetcode-problemset
synced 2025-11-04 03:33:12 +08:00
32 lines
951 B
HTML
32 lines
951 B
HTML
<p>Given a linked list, swap every two adjacent nodes and return its head. You must solve the problem without modifying the values in the list's nodes (i.e., only nodes themselves may be changed.)</p>
|
|
|
|
<p> </p>
|
|
<p><strong class="example">Example 1:</strong></p>
|
|
<img alt="" src="https://assets.leetcode.com/uploads/2020/10/03/swap_ex1.jpg" style="width: 422px; height: 222px;" />
|
|
<pre>
|
|
<strong>Input:</strong> head = [1,2,3,4]
|
|
<strong>Output:</strong> [2,1,4,3]
|
|
</pre>
|
|
|
|
<p><strong class="example">Example 2:</strong></p>
|
|
|
|
<pre>
|
|
<strong>Input:</strong> head = []
|
|
<strong>Output:</strong> []
|
|
</pre>
|
|
|
|
<p><strong class="example">Example 3:</strong></p>
|
|
|
|
<pre>
|
|
<strong>Input:</strong> head = [1]
|
|
<strong>Output:</strong> [1]
|
|
</pre>
|
|
|
|
<p> </p>
|
|
<p><strong>Constraints:</strong></p>
|
|
|
|
<ul>
|
|
<li>The number of nodes in the list is in the range <code>[0, 100]</code>.</li>
|
|
<li><code>0 <= Node.val <= 100</code></li>
|
|
</ul>
|