Data Stream as Disjoint Intervals
A hard-tier problem at 60% community acceptance, tagged with Binary Search, Design, Ordered Set. Reported in interviews at Databricks and 0 others.
You're in an OA at Databricks and hit a problem that looks simple on the surface: track which numbers you've seen in a data stream and return them as disjoint intervals. The trap is that naive interval merging fails under time pressure, and most candidates either over-engineer it or miss edge cases. This is a Hard problem with a 59.5% acceptance rate, which means it punishes sloppy thinking. The trick is choosing the right data structure for insertion and query. If you blank on the pattern during the live assessment, StealthCoder sees the problem, identifies the gap, and surfaces a working solution in seconds, invisible to the proctor.
Companies that ask "Data Stream as Disjoint Intervals"
Data Stream as Disjoint Intervals 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 because the OA filter rejects engineers who'd pass the on-site. That's a broken filter. This is the workaround.
Get StealthCoderThe core challenge is maintaining a sorted collection of disjoint intervals while new integers stream in. You need to find where each new number fits, merge overlapping or adjacent intervals, and handle all the boundary cases. The naive approach iterates through all intervals for each insertion, which kills performance. The real solution uses Binary Search to locate insertion points and an Ordered Set to keep intervals sorted and queryable. Common failures happen when merging intervals with different overlap rules (inclusive vs exclusive bounds) or when you forget that adjacent intervals like [1,2] and [3,4] must merge into [1,4]. Under interview pressure, candidates often implement interval merging correctly but forget to handle the data structure efficiency. StealthCoder's hedge here matters because the problem is dense: you're thinking about comparators, boundary conditions, and set operations all at once.
Pattern tags
You know the problem.
Make sure you actually pass it.
Data Stream as Disjoint Intervals recycles across companies for a reason. It's hard-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 because the OA filter rejects engineers who'd pass the on-site. That's a broken filter. This is the workaround. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Data Stream as Disjoint Intervals interview FAQ
Is this still asked at top companies?+
Yes. Databricks reports it, and the 59.5% acceptance rate suggests it's a genuine filter, not a throwaway. Companies use it to test both design sense and algorithmic precision under time constraints. It's not as saturated as Two Sum, but it's common enough that skipping it is risky.
What's the main trick?+
Use Binary Search to find insertion point, then carefully merge intervals in all directions. The gotcha is that [1,2] and [3,4] are adjacent and should merge into [1,4]. Many candidates implement merging for overlaps but forget adjacency. Ordered Set keeps insertion and lookup efficient.
How do Binary Search and Ordered Set connect here?+
Binary Search pinpoints where a new number fits among existing intervals in O(log n). Ordered Set maintains sorted order without manual sorting after each insertion. Together they give you O(log n) lookup and O(n) merge per insertion, not O(n^2) brute force.
What edge cases kill candidates?+
Empty stream. Single-element intervals. Numbers that extend the leftmost or rightmost interval. Adjacent intervals that must merge. Inserting a number that merges three or more intervals into one. Test all of these before you lock in your solution.
How long should this take in an OA?+
If you've seen the pattern, 25 to 35 minutes for a clean solution. If you haven't, you'll thrash on merging logic and boundary checks. That's exactly when StealthCoder saves you: the problem hits, you blank, and a working solution appears while you keep talking to the interviewer.
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