Missing Ranges
A easy-tier problem at 35% community acceptance, tagged with Array. Reported in interviews at Meta and 2 others.
Missing Ranges is the kind of problem that looks trivial until you hit the edge cases, then suddenly you're staring at a 30% acceptance rate and wondering why. Meta, TikTok, and Google ask it. The trap: candidates think it's about finding gaps in an array, then blank on what "missing" means when you have negative numbers, single-element ranges, or the entire range is present. If this hits your live OA and you freeze on the definition or the formatting, StealthCoder surfaces a working solution in seconds, invisible to the proctor.
Companies that ask "Missing Ranges"
Missing Ranges 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 real trick isn't the algorithm, it's the boundary conditions. You're given a sorted array and an inclusive range (lower and upper bounds), and you have to return all missing contiguous subsequences as strings. The gotcha: you need to handle negatives, handle the gap between each pair of consecutive array elements, and format each range correctly (single number vs. start->end notation). Most candidates skip the detailed case breakdown, forget to check if the number before the array's first element or after its last element creates a gap, or mess up the string formatting. The obvious brute-force approach (check every number in the range) times out on large ranges. The real solution iterates through the array once, comparing each element to the expected next value, and records gaps. StealthCoder hedges the live assessment if you haven't drilled this specific case explosion.
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Missing Ranges recycles across companies for a reason. It's easy-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.
Missing Ranges interview FAQ
Why is the acceptance rate so low for an 'Easy' problem?+
Edge cases. The problem isn't hard algorithmically, but candidates stumble on negative numbers, single-element ranges vs. multi-element ranges, formatting output as strings, and off-by-one errors when comparing consecutive elements. The definition of 'missing' is precise, and one wrong detail tanks the submission.
Is this still asked at Meta, TikTok, and Google?+
Yes. It appears in their assessment reports. It's a favorite for screening because it's short to state but long to code correctly. It tests attention to detail and boundary handling, not just raw algorithmic skill.
What's the core trick to Missing Ranges?+
Single pass through the sorted array, comparing each element to the expected next value in the range. When there's a gap, format it as a single number or a 'start->end' string, then move on. The gaps can appear before the first element, between any two elements, or after the last element.
How does it relate to other array problems?+
It's a stepping stone to merge intervals and interval-related problems. The skill it tests, interval manipulation and boundary handling, shows up in harder problems. Missing Ranges is the 'easy' version where you don't merge or combine ranges, just identify them.
What's the most common failure mode?+
Forgetting to cast or handle the data type correctly when building the missing range strings, or missing the gap between the array's last element and the upper bound. Also, candidates often hardcode the gap logic and miss one of the three boundary cases: before the first element, between elements, and after the last.
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