Merge Nodes in Between Zeros
A medium-tier problem at 90% community acceptance, tagged with Linked List, Simulation. Reported in interviews at josh technology and 0 others.
Merge Nodes in Between Zeros is a medium-difficulty linked list problem with a high acceptance rate (roughly 90%), but that doesn't mean you'll nail it under timed pressure. The trick is realizing you're not just removing zeros, you're collapsing everything between them into a single node whose value is the sum of all intermediate nodes. Josh Technology has asked this. Most candidates either overthink the state machine or bungle the node reassignment logic. StealthCoder runs invisibly during your assessment and surfaces the correct merge pattern instantly if you hit a wall.
Companies that ask "Merge Nodes in Between Zeros"
Merge Nodes in Between Zeros 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 at a top-10 tech company who can solve these problems cold but didn't want to trust himself in a 90-minute screen share.
Get StealthCoderThe problem looks like a standard linked list traversal, but the pattern is simulation plus accumulation. You walk the list, track the current sum between zeros, and when you hit a zero, create a new node with that sum. The gotcha: you can't just modify values in place. You need to actually reconstruct the list by building new nodes and rewiring pointers. The obvious first attempt, trying to skip nodes or modify them on the fly, fails because you lose track of which nodes to keep and how to link them. The correct approach tracks a running sum, discards original nodes between zeros, and only materializes new nodes at boundaries. If you've drilled Linked List and Simulation patterns hard, this is doable. If you haven't, the logic feels awkward in real time. That's where StealthCoder becomes your safety net: if the traversal or pointer logic stalls during the OA, a working solution surfaces in seconds, invisible to the proctor.
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Merge Nodes in Between Zeros 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 at a top-10 tech company who can solve these problems cold but didn't want to trust himself in a 90-minute screen share. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Merge Nodes in Between Zeros interview FAQ
Is Merge Nodes in Between Zeros really that common in interviews?+
Josh Technology has asked it, and the 90% acceptance rate suggests it's a fair problem that trips up candidates who haven't practiced linked list reconstruction. It's not as universal as Two Sum, but it appears in medium-tier rounds.
What's the trick that most candidates miss?+
Trying to modify node values instead of building a new list. The problem requires you to discard nodes between zeros and create fresh nodes with summed values. Pointer reassignment is the real work, not arithmetic.
Can I solve this without creating new nodes?+
Not cleanly. You could theoretically reuse the first node after each zero and zero out the rest, but that's messier and easier to botch. Constructing a fresh list is the standard pattern and clearer under time pressure.
How does this relate to general linked list prep?+
It combines traversal, pointer manipulation, and value accumulation. If you're solid on Two Pointers and basic list reconstruction, this is a logical step. It tests whether you can think beyond simple deletion or reversal.
What edge cases trip people up?+
Empty list or single node, consecutive zeros, and the final node being a zero. Most fail on pointer logic when wiring the last merged node. Test thoroughly before submitting.
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