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leetcode/problem/integer-replacement.html

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+<p>Given a positive integer <code>n</code>,&nbsp;you can apply one of the following&nbsp;operations:</p>
+
+<ol>
+	<li>If <code>n</code> is even, replace <code>n</code> with <code>n / 2</code>.</li>
+	<li>If <code>n</code> is odd, replace <code>n</code> with either <code>n + 1</code> or <code>n - 1</code>.</li>
+</ol>
+
+<p>Return <em>the minimum number of operations needed for <code>n</code> to become <code>1</code></em>.</p>
+
+<p>&nbsp;</p>
+<p><strong>Example 1:</strong></p>
+
+<pre>
+<strong>Input:</strong> n = 8
+<strong>Output:</strong> 3
+<strong>Explanation:</strong> 8 -&gt; 4 -&gt; 2 -&gt; 1
+</pre>
+
+<p><strong>Example 2:</strong></p>
+
+<pre>
+<strong>Input:</strong> n = 7
+<strong>Output:</strong> 4
+<strong>Explanation: </strong>7 -&gt; 8 -&gt; 4 -&gt; 2 -&gt; 1
+or 7 -&gt; 6 -&gt; 3 -&gt; 2 -&gt; 1
+</pre>
+
+<p><strong>Example 3:</strong></p>
+
+<pre>
+<strong>Input:</strong> n = 4
+<strong>Output:</strong> 2
+</pre>
+
+<p>&nbsp;</p>
+<p><strong>Constraints:</strong></p>
+
+<ul>
+	<li><code>1 &lt;= n &lt;= 2<sup>31</sup> - 1</code></li>
+</ul>