Voleon·Software Engineer·Technical Phone Screen·Intermediate

Intermediate

Jun 2026

Summary

Voleon SWE interview had at least one coding round that went straight into a circular game simulation variant. Not a brutal interview but the twist on a known problem meant you couldn't just recite the standard solution.

Questions Asked (1)

Given n friends sitting in a circle, simulate an elimination game where the count-to-eliminate changes each round according to a given array. Return the last remaining friend.

Algorithms & Data Structures

Author's notes

I recognized the base problem pretty fast but the per-round k array threw me for a second.

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AI HintsAI Generated

Suggested Approach

Model the circle as a circular linked list or use an order-statistics tree to efficiently handle eliminations. Simulate each round by advancing the current pointer by (count-1) steps modulo the current number of friends, then remove that friend. Continue until one friend remains.

Pro tip: Clarify the indexing and direction of counting upfront (e.g., 0-indexed, clockwise) to avoid off-by-one errors. Mention that if the count array is large, you can optimize by taking modulo the current circle size.

1. Clarify the problem

Ask questions to confirm: indexing (0 or 1), counting direction, whether the count includes the current person, and what happens if the count array is exhausted (e.g., repeat or stop).

2. Choose a data structure

Decide between a simple array with a list for O(n^2) simulation, a circular linked list for O(n*k) where k is number of rounds, or an order-statistics tree (e.g., Fenwick tree) for O(n log n).

3. Simulate the elimination

Maintain the current position and the current circle size. For each count c, compute the index to remove as (current + c - 1) % size, remove that element, and update current to that index (which now points to the next person).

4. Handle edge cases

Consider n=1, empty count array, counts larger than current size, and negative counts (if allowed). Ensure the loop terminates correctly.

5. Analyze complexity and optimize

State the time and space complexity of your approach. If needed, propose optimizations like using a Fenwick tree to find the k-th remaining person in O(log n) per elimination.

Key Points to Mention

Circular linked list or array simulation with modulo arithmetic
Time complexity: O(n * m) for naive simulation, O(n log n) with Fenwick tree
Space complexity: O(n) for storing the circle
Handling of count array: whether to cycle through counts or stop when exhausted
Edge cases: n=1, count=0, count > current size
Modulo operation to wrap around the circle and avoid unnecessary steps

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.