Concatenation of Array
A easy-tier problem at 90% community acceptance, tagged with Array, Simulation. Reported in interviews at GE Healthcare and 0 others.
Concatenation of Array is an easy problem that looks trivial on the surface, which is exactly why it catches candidates off guard during live assessments. GE Healthcare has asked it, and with a 90% acceptance rate, you'd think it's a freebie. The trap: overthinking a simulation problem that's actually about understanding what the problem statement is really asking. If you misread the input format or the expected output shape, you'll waste time debugging the wrong thing. StealthCoder runs invisible during your assessment and surfaces a working solution in seconds if you blank on the exact output format or get tangled in array indexing.
Companies that ask "Concatenation of Array"
Concatenation of Array 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. Made by an Amazon engineer who watched the leaked-problem repo become an industry secret. He decided you should have it too.
Get StealthCoderThe problem is a pure simulation task: given an array, concatenate it with itself and return the result. There's no algorithmic complexity here, no dynamic programming, no graph traversal. The real difficulty is parsing what the problem wants and executing it cleanly without off-by-one errors. Most candidates rush and either misunderstand the input shape, concatenate the wrong number of times, or return the result in an unexpected format. The obvious approach is correct: iterate once, push all elements of the input array twice to a result array. Common pitfall: forgetting that you're concatenating the array with itself, not with a modified version. Read the problem statement word for word. If you hit this during a live OA and freeze on interpretation, StealthCoder solves it instantly so you can move on to harder problems.
Pattern tags
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Make sure you actually pass it.
Concatenation of Array 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. Made by an Amazon engineer who watched the leaked-problem repo become an industry secret. He decided you should have it too. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Concatenation of Array interview FAQ
Is Concatenation of Array really asked at tech companies?+
Yes, GE Healthcare has reported asking it. Easy problems often appear early in assessment loops as warm-ups or screening filters. A 90% acceptance rate means most who attempt it succeed, but that also means companies use it to spot careless candidates who rush through simple tasks.
What's the trick to this problem?+
There isn't one algorithmically. The trick is reading the problem statement carefully and understanding the input format. No nested loops, no sorting, no data structure tricks. Just simulation. Miss one detail and you'll return the wrong shape.
How is Concatenation of Array different from other Array problems?+
It's pure simulation with no algorithmic depth. Most Array problems involve searching, sorting, or two-pointer techniques. This one tests attention to detail and clean implementation. It's a filter for candidates who skim requirements.
Can I solve this without extra space?+
Depending on the problem variant, you may be required to return a new array, which means you can't avoid O(n) extra space. Check the output format carefully. If in-place modification is required, that changes the approach.
Should I spend time practicing this problem?+
Not heavily. A 90% acceptance rate and easy difficulty mean the fundamentals are more important. Drill Array and Simulation basics, understand input/output formats, then move to medium problems. This problem is a warmup, not a blocker.
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