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.
Examples
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
2007. Find Original Array From Doubled Array
Medium
30 Points
Array
Hash Table
Greedy
Sorting
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.
Examples
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
Find Original Array From Doubled Array - Practice Coding | SlaveCode