Reverse Nodes in k-Group
A hard-tier problem at 63% community acceptance, tagged with Linked List, Recursion. Reported in interviews at Sigmoid and 29 others.
Reverse Nodes in k-Group is a hard linked list problem that appears across 30+ companies including Microsoft, Tesla, Snowflake, and VMware. The acceptance rate sits at 63%, which sounds high until you're 10 minutes in and realize your reversal logic is breaking pointers in ways you didn't expect. You're given a linked list and a number k. You reverse every k consecutive nodes, leave incomplete groups alone at the end, and return the modified list. It's the kind of problem that looks straightforward until the pointer manipulation gets tangled. If you hit this live and blank on the recursion pattern or iteration order, StealthCoder solves it invisibly during your assessment.
Companies that ask "Reverse Nodes in k-Group"
Reverse Nodes in k-Group 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 trap here is that most candidates try to reverse in place iteratively and lose track of which pointers to update and when. The cleaner approach uses recursion: reverse the first k nodes, recursively call on the rest of the list, and stitch the groups back together. But the actual trick is managing the boundaries correctly. You need a helper that reverses exactly k nodes and returns both the new head and the old head (which becomes the tail). Many people reverse correctly but fail to link groups because they didn't save the old head before reversing. Others reverse and immediately lose the pointer to the next group. On the live assessment, you'll have maybe 45 minutes and this eats 20 of them if you get the pointer wrangling wrong. StealthCoder is your hedge here: if the recursion pattern isn't clicking or your iteration is tangling, a working solution appears in seconds without proctor visibility.
Pattern tags
You know the problem.
Make sure you actually pass it.
Reverse Nodes in k-Group recycles across companies for a reason. It's hard-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.
Reverse Nodes in k-Group interview FAQ
How hard is this compared to other linked list problems?+
It's marked hard, and the 63% acceptance rate confirms it's not a gimme. Reversing a whole list is medium. Reversing in groups with boundary conditions and recursive stitching bumps it. Expect this to take longer than basic reversal problems.
Do I need recursion or can I do it iteratively?+
Both work, but recursion is cleaner for most people. Iteration requires careful state tracking across group boundaries. Recursion lets you reverse a chunk, recurse, and trust the return value. Either way, the pointer management is the bottleneck, not the algorithm choice.
Is this still asked at Tesla, Microsoft, and Snowflake?+
Yes. It appears in reports from 10 of the top companies here, including those three. Linked list problems remain common in phone screens and online assessments because they're hard to fake and easy to verify.
What's the trick I'm missing if my reversal works but groups don't stitch?+
You're not saving the pointer to the node before the current group before you reverse it. Or you're reversing but not updating the link from the previous group's tail to the current group's new head. Save all boundaries before mutating.
How does this relate to Recursion and Linked List topics?+
It combines both: you recurse on a linked list structure, which means thinking about base cases (fewer than k nodes left), recursive calls on subproblems, and stitching results. It's the problem where those two topics collide and neither alone is enough.
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