Merge Arrays
Reported by candidates from IBM's online assessment. Pattern, common pitfall, and the honest play if you blank under the timer.
IBM's Merge Arrays problem hit the OA circuit in February 2024 and it's a straightforward array manipulation question that catches people off guard because they overthink it. The core task is combining two or more arrays into a single result, but the trick is in the edge cases and the efficiency of your approach. If you blank on the logic during the live assessment, StealthCoder will read the problem and hand you the pattern in seconds so you can code with confidence.
Pattern and pitfall
Merge Arrays is a classic array problem that tests whether you understand iteration, index management, and avoiding unnecessary allocations. Most candidates start by concatenating arrays naively, which works but wastes space and time. The real pattern is a two-pointer or linear scan approach, depending on whether the input arrays are sorted. The common pitfall is not handling empty arrays or single-element arrays cleanly. In a live OA, if you freeze on the implementation details, StealthCoder acts as your safety net by surfacing the exact merge strategy you need. The problem itself is low-difficulty, so execution speed and clean code matter more than algorithmic brilliance.
If you see this problem in your OA tomorrow, the play is to recognize the pattern in 30 seconds. StealthCoder buys you that recognition.
You can drill Merge Arrays 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. Built by an Amazon engineer who passed his OA cold and still thinks the filter is broken.
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This OA pattern shows up on LeetCode as merge sorted array. If you have time before the OA, drill that.
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IBM reuses patterns across OAs. Built by an Amazon engineer who passed his OA cold and still thinks the filter is broken. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Merge Arrays FAQ
Is this asking me to merge sorted arrays or just combine them?+
The problem title alone doesn't specify sorting, so assume you're just concatenating or combining arrays as-is. If the input is sorted, that's mentioned in the problem statement. IBM's version in February 2024 is a basic merge, not a merge-sorted-arrays variant. Read the exact constraints carefully during the OA.
What's the trick here?+
There isn't a complex algorithmic trick. The trap is overcomplicating it or using extra space when you don't need to. Write clean, readable code that handles empty inputs and multiple arrays without nested loops where possible. Efficiency comes from simplicity, not cleverness.
How much time should this take?+
If you understand the pattern, 10-15 minutes of coding. If you're unsure about edge cases or array syntax in your language, 20-25 minutes. This is not a long-burn problem, so if you're stuck past 20 minutes, move on and come back.
Do I need to modify the input arrays or return a new one?+
The problem statement will specify. Usually it's return a new merged array, not in-place. But always confirm the output format and return type during the OA before you start coding.
What language should I use?+
Use whatever you're most comfortable with. Array operations and iteration are identical across Python, Java, JavaScript, and C++. Pick the one where you won't make syntax mistakes under pressure. Speed of coding matters more than language choice here.