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leetcode/problem/binary-tree-right-side-view.html

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+<p>Given the <code>root</code> of a binary tree, imagine yourself standing on the <strong>right side</strong> of it, return <em>the values of the nodes you can see ordered from top to bottom</em>.</p>
+
+<p>&nbsp;</p>
+<p><strong>Example 1:</strong></p>
+<img alt="" src="https://assets.leetcode.com/uploads/2021/02/14/tree.jpg" style="width: 401px; height: 301px;" />
+<pre>
+<strong>Input:</strong> root = [1,2,3,null,5,null,4]
+<strong>Output:</strong> [1,3,4]
+</pre>
+
+<p><strong>Example 2:</strong></p>
+
+<pre>
+<strong>Input:</strong> root = [1,null,3]
+<strong>Output:</strong> [1,3]
+</pre>
+
+<p><strong>Example 3:</strong></p>
+
+<pre>
+<strong>Input:</strong> root = []
+<strong>Output:</strong> []
+</pre>
+
+<p>&nbsp;</p>
+<p><strong>Constraints:</strong></p>
+
+<ul>
+	<li>The number of nodes in the tree is in the range <code>[0, 100]</code>.</li>
+	<li><code>-100 &lt;= Node.val &lt;= 100</code></li>
+</ul>