<h2><a href="https://leetcode.com/problems/powx-n/">50. Pow(x, n)</a></h2><h3>Medium</h3><hr><div><p>Implement <a href="http://www.cplusplus.com/reference/valarray/pow/" target="_blank">pow(x, n)</a>, which calculates <code>x</code> raised to the power <code>n</code> (i.e., <code>xⁿ</code>).</p>

<p>&nbsp;</p>

<p><strong class="example">Example 1:</strong></p>

<pre><strong>Input:</strong> x = 2.00000, n = 10

<strong>Output:</strong> 1024.00000

</pre>

<p><strong class="example">Example 2:</strong></p>

<pre><strong>Input:</strong> x = 2.10000, n = 3

<strong>Output:</strong> 9.26100

</pre>

<p><strong class="example">Example 3:</strong></p>

<pre><strong>Input:</strong> x = 2.00000, n = -2

<strong>Output:</strong> 0.25000

<strong>Explanation:</strong> 2^-2 = 1/2² = 1/4 = 0.25

</pre>

<p>&nbsp;</p>

<p><strong>Constraints:</strong></p>

<ul>

<li><code>-100.0 &lt; x &lt; 100.0</code></li>

<li><code>-2³¹ &lt;= n &lt;= 2³¹-1</code></li>

<li><code>n</code> is an integer.</li>

<li>Either <code>x</code> is not zero or <code>n &gt; 0</code>.</li>

<li><code>-10⁴ &lt;= xⁿ &lt;= 10⁴</code></li>

</ul>

</div>