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How to Solve Find Original Array From Doubled Array Problem
Master the Find Original Array From Doubled Array LeetCode problem with undetectable real-time assistance. Get instant solutions and explanations during your coding interviews.
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Start Free for WindowsMedium#2007
LeetCode ProblemFind Original Array From Doubled Array
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.
ArrayHash TableGreedySorting
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Problem Breakdown
Understanding the Find Original Array From Doubled Array Problem
Let's break down this LeetCode problem and understand what makes it challenging in interview settings.
Problem Statement
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.
MediumProblem #2007
LeetCodeFind Original Array From Doubled Array
Related Topics
ArrayHash TableGreedySorting
How Phantom Code Helps
Get real-time assistance for Find Original Array From Doubled Array problems during coding interviews. Phantom Code provides instant solutions and explanations.
Examples
# Example 1
Input
changed = [1,3,4,2,6,8]
Output
[1,3,4]
# Example 2
Input
changed = [6,3,0,1]
Output
[]
# Example 3
Input
changed = [1]
Output
[]
Constraints
1 <= changed.length <= 105
0 <= changed[i] <= 105
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Solve Find Original Array From Doubled Array — An integer array original is transformed into a doubled array changed by appendi...
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def solve(input):
# Optimal O(n) solution
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Time: O(n) | Space: O(n)
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Frequently Asked Questions
Common questions about solving Find Original Array From Doubled Array and using Phantom Code during coding interviews.
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Phantom Code generates complete solutions instantly with proper complexity analysis, letting you focus on explaining your approach and demonstrating problem-solving skills rather than getting stuck on implementation details during high-pressure situations.
What if the interviewer asks follow-up questions or modifications to problems like Find Original Array From Doubled Array?
Phantom Code adapts in real-time. Screenshot the modified problem or use audio mode to capture the interviewer's follow-up, and get an updated solution within seconds — including edge cases and optimizations.
Can Phantom Code help me communicate my solution for problems like Find Original Array From Doubled Array?
Yes. Phantom Code provides step-by-step approach explanations with 3 progressive thoughts, so you can walk through your solution naturally. It also provides time and space complexity analysis to discuss trade-offs.
How does Phantom Code assist with different programming languages for Find Original Array From Doubled Array type problems?
Phantom Code supports 11 programming languages including Python, Java, C++, JavaScript, TypeScript, Go, Rust, Ruby, Swift, Kotlin, and C#. Set your preferred language and get idiomatic solutions.
What coding mistakes does Phantom Code help me avoid during Find Original Array From Doubled Array interviews?
Phantom Code catches common mistakes like off-by-one errors, missing edge cases, incorrect base conditions, and suboptimal approaches. It provides clean, well-structured code that handles all edge cases.
Is Phantom Code detectable when solving problems like Find Original Array From Doubled Array during live interviews?
No. Phantom Code runs as an invisible desktop overlay that doesn't appear in screen shares, recordings, or proctoring software. It works with Zoom, HackerRank, CodeSignal, CoderPad, and all major platforms.
How does Phantom Code help when I'm struggling with Find Original Array From Doubled Array style questions under pressure?
The AI provides structured guidance: first the approach (what algorithm/data structure to use and why), then the implementation with clean code, and finally complexity analysis. This helps you think clearly even under pressure.
Does Phantom Code work for the coding platforms used in Find Original Array From Doubled Array interviews?
Yes. Phantom Code works with all major coding platforms including LeetCode, HackerRank, CodeSignal, CoderPad, HackerEarth, and any browser-based coding environment.
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