Find Consecutive Integers from a Data Stream
A medium-tier problem at 49% community acceptance, tagged with Hash Table, Design, Queue. Reported in interviews at Intel and 0 others.
You're streaming data in real time and need to find consecutive integers on the fly. Intel asks this one, and it's a design problem that trips up candidates who overthink the state management. Most people jump straight to sorting or range-checking without building the right data structure first. The acceptance rate sits below 50%, which means half the field either mis-designs their solution or gets tangled in edge cases around the stream semantics. If this problem hits your live assessment and you freeze on the architecture, StealthCoder surfaces a working solution in seconds, invisible to the proctor.
Companies that ask "Find Consecutive Integers from a Data Stream"
Find Consecutive Integers from a Data Stream is the kind of problem that decides whether you pass. StealthCoder reads the problem on screen and surfaces a working solution in under 2 seconds. Invisible to screen share. The proctor sees nothing. Built by an Amazon engineer who used it to pass JPMorgan's OA and system design loop.
Get StealthCoderThe trick is maintaining a hash table (or set) of recent integers and a queue to track insertion order, so you can efficiently query whether a consecutive sequence exists and evict stale elements. Most candidates default to sorting after each insert, which tanks performance. Others try to maintain all possible ranges, which blows up memory. The real pattern is lazy deletion: insert into a set, add to queue, and only compute consecutive sequences when explicitly asked. Hash table gives you O(1) lookups; queue handles the sliding window or time-window constraint if one exists. Common failure mode: confusing "consecutive" with "in order of arrival." Consecutive means numeric adjacency, not insertion order. If you haven't drilled this design pattern before, StealthCoder hedges the live OA by providing the correct data-structure skeleton and eviction logic instantly.
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Find Consecutive Integers from a Data Stream recycles across companies for a reason. It's medium-tier, and most candidates blank under the timer. StealthCoder is the hedge: an AI overlay invisible during screen share. It reads the problem and surfaces a working solution in under 2 seconds. Built by an Amazon engineer who used it to pass JPMorgan's OA and system design loop. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Find Consecutive Integers from a Data Stream interview FAQ
Is this problem really about just counting or is there more to it?+
It's primarily a design and hash table problem. Counting is part of the solution (how many consecutive integers from a starting point), but the hard part is deciding what data structure stores the stream and how to efficiently check consecutive sequences without recomputing every time.
Does this problem assume a time window or a fixed-size buffer?+
The input problem statement would specify. Common variants include sliding windows or fixed buffers. Without explicit constraints in the OA, assume you're storing all recent integers and computing on demand. Queue often handles eviction order, but confirm the constraint during the assessment.
Why do so many people fail this at ~50% acceptance?+
Candidates often over-engineer state management (sorting on every insert, maintaining all range metadata) or misunderstand what consecutive means. A clean hash table plus queue design solves it, but the design step itself is where people stumble.
Does the consecutive sequence have to start from a specific integer?+
Typically no. The problem asks you to find the longest or any consecutive sequence from the integers you've seen. The algorithm searches from each integer in your set to see how far the sequence extends, using hash table O(1) lookups.
Will I see this at other companies besides Intel?+
Intel is the only company explicitly in the data for this problem. That said, stream-processing and hash-table design patterns are common across tech interviews, so similar problems appear elsewhere. Drills the same fundamentals.
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