Make K-Subarray Sums Equal
A medium-tier problem at 37% community acceptance, tagged with Array, Math, Greedy. Reported in interviews at Morgan Stanley and 0 others.
Make K-Subarray Sums Equal is a medium-difficulty problem that hits you with a constraint most candidates don't see coming. Morgan Stanley has asked this one. You're handed an array and told to split it into K subarrays such that all K sums are identical. The acceptance rate sits at 37%, which means more than half the people who attempt it walk away stuck. The trap is obvious: you can't always solve it by greedy splitting alone. There's a number-theoretic layer that most candidates miss on first read. If this problem surfaces during your live assessment and you haven't drilled the GCD-based insight, StealthCoder solves it invisibly in seconds.
Companies that ask "Make K-Subarray Sums Equal"
Make K-Subarray Sums Equal 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 core trick is recognizing that the target sum (total sum divided by K) is only achievable if certain divisibility constraints hold. Specifically, you need to think about the greatest common divisor of differences and the constraints imposed by subarray contiguity. Most candidates attempt a greedy left-to-right partition and fail when the problem requires you to first validate whether a solution even exists. The number theory and sorting angles aren't decorative. Pitfall: jumping into a simulation without checking the mathematical precondition. Pitfall: misunderstanding how subarray boundaries force constraints on which sums are reachable. When you hit this live and the greedy approach crumbles, StealthCoder surfaces the correct GCD-based or modulo-based validation step and the construction algorithm behind it.
Pattern tags
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Make K-Subarray Sums Equal recycles across companies for a reason. It's medium-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.
Make K-Subarray Sums Equal interview FAQ
Is this still asked at big tech and finance companies?+
Morgan Stanley has publicly reported it. It's a mid-level array problem, so it lands in phone or online assessment rounds at firms with quantitative hiring pipelines. Not as ubiquitous as two-sum, but narrow enough that skipping it is risky.
What's the real trick if greedy splitting doesn't work?+
The problem often requires validating divisibility or GCD constraints before you even attempt to partition. Many candidates skip this validation and waste 20+ minutes on failed greedy attempts. Check whether a valid solution structure can exist mathematically before building it.
How does number theory actually apply here?+
The sum of all K subarrays must equal the total sum, and each subarray sum must be identical. That forces the total sum to be divisible by K. Beyond that, GCD of differences or modular arithmetic often determines whether valid partitions exist and how to construct them efficiently.
What's the typical time complexity I should aim for?+
Most optimal solutions run in O(n log n) or O(n) depending on approach, often due to sorting or single-pass validation. Brute force O(n^2) partitioning will time out on large inputs, which is why the mathematical insight is critical.
Is this harder than other medium array problems?+
The 37% acceptance rate says yes. It's not about implementation complexity; it's about spotting the number-theoretic precondition that most candidates skip. Once you see it, the problem becomes straightforward.
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