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# 0342. Power of Four

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

## Description

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

An integer `n` is a power of four, if there exists an integer `x` such that `n == 4x`.

**Example 1:**

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

**Example 2:**

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

**Example 3:**

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

**Constraints:**

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

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

## ac

```java
```