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+<h2><a href="https://leetcode.com/problems/merge-two-sorted-lists/">21. Merge Two Sorted Lists</a></h2><h3>Easy</h3><hr><div><p>You are given the heads of two sorted linked lists <code>list1</code> and <code>list2</code>.</p>
+
+<p>Merge the two lists in a one <strong>sorted</strong> list. The list should be made by splicing together the nodes of the first two lists.</p>
+
+<p>Return <em>the head of the merged linked list</em>.</p>
+
+<p>&nbsp;</p>
+<p><strong>Example 1:</strong></p>
+<img alt="" src="https://assets.leetcode.com/uploads/2020/10/03/merge_ex1.jpg" style="width: 662px; height: 302px;">
+<pre><strong>Input:</strong> list1 = [1,2,4], list2 = [1,3,4]
+<strong>Output:</strong> [1,1,2,3,4,4]
+</pre>
+
+<p><strong>Example 2:</strong></p>
+
+<pre><strong>Input:</strong> list1 = [], list2 = []
+<strong>Output:</strong> []
+</pre>
+
+<p><strong>Example 3:</strong></p>
+
+<pre><strong>Input:</strong> list1 = [], list2 = [0]
+<strong>Output:</strong> [0]
+</pre>
+
+<p>&nbsp;</p>
+<p><strong>Constraints:</strong></p>
+
+<ul>
+	<li>The number of nodes in both lists is in the range <code>[0, 50]</code>.</li>
+	<li><code>-100 &lt;= Node.val &lt;= 100</code></li>
+	<li>Both <code>list1</code> and <code>list2</code> are sorted in <strong>non-decreasing</strong> order.</li>
+</ul>
+</div>
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