Description
Given a changed array formed by appending doubled values of original array and shuffling, return the original array or empty if impossible.
Examples
Input:
changed = [1,3,4,2,6,8]Output:
[1,3,4]Explanation:
Original array doubled.
Input:
changed = [6,3,0,1]Output:
[]Explanation:
Edge case with empty result.
Input:
changed = [0,0,0,0]Output:
[0,0]Explanation:
When the original array contains zeros, each zero pairs with another zero (since 0 * 2 = 0). With 4 zeros total, it is possible to form 2 pairs, so the original array is [0,0].
Constraints
- •
1 ≤ changed.length ≤ 10⁵