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Array interview questions test index manipulation, in-place work and the instinct to trade memory for time — the most common coding round starting point.
Array problems are the most common opening move in a coding interview, because they let an interviewer watch you reason about indices, bounds and complexity without any exotic data structure getting in the way. Most array questions reduce to one of a handful of patterns: a single pass with a running aggregate, two indices moving toward each other, a sliding window over a contiguous range, or a hash map trading space for a second pass.
Interviewers are usually less interested in whether you find the optimal solution than in how you get there. Stating the brute force first, naming its complexity, then identifying the specific repeated work that a hash map or a second pointer removes is the sequence that reads as competence. Off-by-one errors and unhandled empty inputs are what actually sink otherwise correct answers, so walking a concrete example through your own code before declaring it done is worth the sixty seconds.
24 coding · 8/12/4 easy/medium/hard
Two pointers, sliding window, prefix sums, and hash-map lookups cover the large majority of array questions asked in real loops. Learning those four patterns transfers further than memorising individual problems.
They are the most frequently used warm-up in coding rounds at large tech companies, and often the first of two questions in a 45-minute screen — which means solving them quickly buys time for the harder second question.