Count Integers in Intervals
A hard-tier problem at 34% community acceptance, tagged with Design, Segment Tree, Ordered Set. Reported in interviews at LinkedIn and 1 others.
Count Integers in Intervals is a hard design problem that shows up in interviews at LinkedIn and Databricks. You're building a data structure that tracks intervals and answers count queries in real time. The 34% acceptance rate tells you most candidates either build something that works but is too slow, or they freeze when they realize a naive approach won't cut it. This is the kind of problem where the interviewer watches you optimize, not just code. If you hit this live and your first solution times out, StealthCoder surfaces the segment tree or ordered set pattern in seconds, keeping you from spiraling.
Companies that ask "Count Integers in Intervals"
Count Integers in 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 by an engineer who got tired of watching his cohort grind for six months and still get filtered at the OA stage.
Get StealthCoderThe trap is thinking you can just store intervals and iterate through them on every query. Once you add a few hundred intervals, that becomes O(n) per count, and you fail. The real pattern lives in segment trees or ordered sets that track interval endpoints and counts. You need to either build a segment tree to query ranges, or use an ordered map to efficiently merge and split intervals while maintaining counts. The hard part isn't the algorithm, it's recognizing which data structure fits your constraints and implementing it without bugs under pressure. Most candidates know the names but can't execute fast enough. When the OA timer is running, StealthCoder executes the working solution while you focus on explaining your thinking.
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Count Integers in 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 by an engineer who got tired of watching his cohort grind for six months and still get filtered at the OA stage. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Count Integers in Intervals interview FAQ
Is this really asked at senior levels or just screening?+
LinkedIn and Databricks both ask it. It's a design and optimization problem, not a pattern-match, so it tests how you think under constraints. It appears in technical screens where they want to see your data structure knowledge.
Do I need to implement a full segment tree or is there a simpler way?+
An ordered set with interval merging can work, but the segment tree approach is cleaner for range queries. Either way, the bottleneck is implementation speed. Know both patterns before you interview.
What's the actual trick that makes this hard?+
Recognizing that naive interval iteration fails, and knowing when to reach for a segment tree versus an ordered map. Most candidates get stuck between choosing the structure and implementing it correctly in time.
How does this relate to the Segment Tree and Ordered Set topics?+
It's a direct application. You use Segment Tree for efficient range counting, or Ordered Set to keep intervals sorted and mergeable. The problem tests whether you can pick the right tool and deploy it.
Will I see interval problems across multiple OAs if I apply to big tech?+
Yes. Interval problems are common at scale-focused companies. If this one hits your assessment, you should have a segment tree and ordered set template ready before you interview.
Want the actual problem statement? View "Count Integers in Intervals" on LeetCode →