Project Notes

Power of Two

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Description

tab: English
 
<p>Given an integer <code>n</code>, return <em><code>true</code> if it is a power of two. Otherwise, return <code>false</code></em>.</p>
 
<p>An integer <code>n</code> is a power of two, if there exists an integer <code>x</code> such that <code>n == 2<sup>x</sup></code>.</p>
 
<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
 
<pre>
<strong>Input:</strong> n = 1
<strong>Output:</strong> true
<strong>Explanation: </strong>2<sup>0</sup> = 1
</pre>
 
<p><strong class="example">Example 2:</strong></p>
 
<pre>
<strong>Input:</strong> n = 16
<strong>Output:</strong> true
<strong>Explanation: </strong>2<sup>4</sup> = 16
</pre>
 
<p><strong class="example">Example 3:</strong></p>
 
<pre>
<strong>Input:</strong> n = 3
<strong>Output:</strong> false
</pre>
 
<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>
 
<ul>
	<li><code>-2<sup>31</sup> &lt;= n &lt;= 2<sup>31</sup> - 1</code></li>
</ul>
 
<p>&nbsp;</p>
<strong>Follow up:</strong> Could you solve it without loops/recursion?
 
 
---
 
[submissions](https://leetcode.com/problems/power-of-two/submissions/) | [solutions](https://leetcode.com/problems/power-of-two/solutions/)
 
 
tab: 中文
 
<p>给你一个整数 <code>n</code>，请你判断该整数是否是 2 的幂次方。如果是，返回 <code>true</code> ；否则，返回 <code>false</code> 。</p>
 
<p>如果存在一个整数 <code>x</code> 使得&nbsp;<code>n == 2<sup>x</sup></code> ，则认为 <code>n</code> 是 2 的幂次方。</p>
 
<p>&nbsp;</p>
 
<p><strong>示例 1：</strong></p>
 
<pre>
<strong>输入：</strong>n = 1
<strong>输出：</strong>true
<strong>解释：</strong>2<sup>0</sup> = 1
</pre>
 
<p><strong>示例 2：</strong></p>
 
<pre>
<strong>输入：</strong>n = 16
<strong>输出：</strong>true
<strong>解释：</strong>2<sup>4</sup> = 16
</pre>
 
<p><strong>示例 3：</strong></p>
 
<pre>
<strong>输入：</strong>n = 3
<strong>输出：</strong>false
</pre>
 
<p>&nbsp;</p>
 
<p><strong>提示：</strong></p>
 
<ul>
	<li><code>-2<sup>31</sup> &lt;= n &lt;= 2<sup>31</sup> - 1</code></li>
</ul>
 
<p>&nbsp;</p>
 
<p><strong>进阶：</strong>你能够不使用循环/递归解决此问题吗？</p>
 
 
 
---
 
[提交记录](https://leetcode.cn/problems/power-of-two/submissions/) | [题解](https://leetcode.cn/problems/power-of-two/solution/)

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