# 0231. Power of Two

<https://leetcode.com/problems/power-of-two>

## Description

Given an integer `n`, return *`true` if it is a power of two. Otherwise, return `false`*.

An integer `n` is a power of two, if there exists an integer `x` such that `n == 2x`.

**Example 1:**

```
**Input:** n = 1
**Output:** true
**Explanation:** 20 = 1
```

**Example 2:**

```
**Input:** n = 16
**Output:** true
**Explanation:** 24 = 16
```

**Example 3:**

```
**Input:** n = 3
**Output:** false
```

**Example 4:**

```
**Input:** n = 4
**Output:** true
```

**Example 5:**

```
**Input:** n = 5
**Output:** false
```

**Constraints:**

* `-231 <= n <= 231 - 1`

**Follow up:** Could you solve it without loops/recursion?

## ac

```java
```