# 2007. Find Original Array From Doubled Array

<https://leetcode.com/problems/find-original-array-from-doubled-array>

## Description

An integer array `original` is transformed into a **doubled** array `changed` by appending **twice the value** of every element in `original`, and then randomly **shuffling** the resulting array.

Given an array `changed`, return `original` *if* `changed` *is a **doubled** array. If* `changed` *is not a **doubled** array, return an empty array. The elements in* `original` *may be returned in **any** order*.

**Example 1:**

```
**Input:** changed = [1,3,4,2,6,8]
**Output:** [1,3,4]
**Explanation:** One possible original array could be [1,3,4]:
- Twice the value of 1 is 1 * 2 = 2.
- Twice the value of 3 is 3 * 2 = 6.
- Twice the value of 4 is 4 * 2 = 8.
Other original arrays could be [4,3,1] or [3,1,4].
```

**Example 2:**

```
**Input:** changed = [6,3,0,1]
**Output:** []
**Explanation:** changed is not a doubled array.
```

**Example 3:**

```
**Input:** changed = [1]
**Output:** []
**Explanation:** changed is not a doubled array.
```

**Constraints:**

* `1 <= changed.length <= 105`
* `0 <= changed[i] <= 105`

## ac

```java
```