2007. Find Original Array From Doubled Array && 954. Array of Doubled Pairs

2007. Find Original Array From Doubled Array Hint 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 = [6,3,0,0,1] Output: [] Explanation: changed is not a doubled array. 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].