public class Solution
extends Object
2007 - Find Original Array From Doubled Array\.
Medium
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