Unaligned Dedupe
Reported by candidates from Rubrik's online assessment. Pattern, common pitfall, and the honest play if you blank under the timer.
Rubrik's September OA included a deduplication problem with a twist: the input isn't cleanly aligned. You're seeing duplicate values, but they arrive in unexpected order or format, and you need to strip them out without breaking the data structure. This is a hash-table pattern in disguise. The trick is recognizing that 'unaligned' means you can't assume sorted input or predictable positioning. StealthCoder will catch the pattern in real time if you blank on the dedup logic during the live assessment.
Pattern and pitfall
The core move is a hash set or hash map to track what you've already seen, then iterate through the input once. The 'unaligned' part means the duplicates aren't adjacent, so a two-pointer or in-place swap won't work cleanly. You're building a set of seen values as you go, and either filtering them out or marking them. The common pitfall is overthinking the 'unaligned' framing and trying a greedy or sorting approach when hash-table lookup is O(1) and does the job. Space is O(n) worst case, time is O(n). StealthCoder feeds you the pattern and the basic structure so you don't freeze up if the wording throws you.
Memorize the pattern. If you can't, run StealthCoder. The proctor sees the IDE. They don't see what's behind it.
You can drill Unaligned Dedupe cold, or you can hedge it. StealthCoder runs invisibly during screen share and surfaces a working solution in under 2 seconds. The proctor sees the IDE. They don't see what's behind it. Made by an engineer who treats the OA as theater. If yours is tonight, you don't have time to grind. You have time to hedge.
Get StealthCoderRelated leaked OAs
This OA pattern shows up on LeetCode as remove duplicates from sorted array. If you have time before the OA, drill that.
You've seen the question.
Make sure you actually pass Rubrik's OA.
Rubrik reuses patterns across OAs. Made by an engineer who treats the OA as theater. If yours is tonight, you don't have time to grind. You have time to hedge. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Unaligned Dedupe FAQ
Does 'unaligned' mean the input is unsorted?+
Yes, and it means duplicates won't cluster together. Don't assume you can solve this with pointers or in-place swaps on a sorted array. Use a hash set to track seen values regardless of position.
Should I preserve order?+
The problem doesn't specify, but assume yes unless told otherwise. Iterate once, build a set of seen values, and output the first occurrence of each unique item in encounter order.
Is this the same as LeetCode 217 or 287?+
Similar pattern, different flavor. This is closer to 'remove duplicates' logic (like LeetCode 26 or 80) but on unordered input. Hash set is your friend here, not sorting.
What if there are multiple fields or nested structures?+
You may need to hash on a specific field or combine fields into a tuple. Read the input spec carefully. The dedup logic stays the same: hash set tracks what you've seen.
How do I prep in 48 hours?+
Memorize the hash-set dedup pattern. Write it out twice from scratch. Know the syntax for your language's set and how to iterate and filter. That's 90% of the battle.