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| 1 | +<h2><a href="https://leetcode.com/problems/swapping-nodes-in-a-linked-list/">1721. Swapping Nodes in a Linked List</a></h2><h3>Medium</h3><hr><div><p>You are given the <code>head</code> of a linked list, and an integer <code>k</code>.</p> |
| 2 | + |
| 3 | +<p>Return <em>the head of the linked list after <strong>swapping</strong> the values of the </em><code>k<sup>th</sup></code> <em>node from the beginning and the </em><code>k<sup>th</sup></code> <em>node from the end (the list is <strong>1-indexed</strong>).</em></p> |
| 4 | + |
| 5 | +<p> </p> |
| 6 | +<p><strong>Example 1:</strong></p> |
| 7 | +<img alt="" src="https://assets.leetcode.com/uploads/2020/09/21/linked1.jpg" style="width: 400px; height: 112px;"> |
| 8 | +<pre><strong>Input:</strong> head = [1,2,3,4,5], k = 2 |
| 9 | +<strong>Output:</strong> [1,4,3,2,5] |
| 10 | +</pre> |
| 11 | + |
| 12 | +<p><strong>Example 2:</strong></p> |
| 13 | + |
| 14 | +<pre><strong>Input:</strong> head = [7,9,6,6,7,8,3,0,9,5], k = 5 |
| 15 | +<strong>Output:</strong> [7,9,6,6,8,7,3,0,9,5] |
| 16 | +</pre> |
| 17 | + |
| 18 | +<p> </p> |
| 19 | +<p><strong>Constraints:</strong></p> |
| 20 | + |
| 21 | +<ul> |
| 22 | + <li>The number of nodes in the list is <code>n</code>.</li> |
| 23 | + <li><code>1 <= k <= n <= 10<sup>5</sup></code></li> |
| 24 | + <li><code>0 <= Node.val <= 100</code></li> |
| 25 | +</ul> |
| 26 | +</div> |
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