Optiver Software Engineer Phone Screen Questions

Hey, I recently passed the behavioral phone call with Optiver and am now preparing for the technical round. While I expect the focus to be on DSA, I want to prep a little system design too. I have not

Recently scheduled optiver r1 technical for swe intern. Anyone mind sharing what types of questions they ask/how you would prepare?

Title. I did my technical phone for Optiver NG SWE last week and will do the final rounds this Friday. To be honest, I didn't think I'd make it this far and I thought new grads won't be asked sys desi

## Problem You are given an encoded array `diff` of length `n-1` where `diff[i] = original[i+1] - original[i]`. You are also given `original[0]`. Reconstruct and return the full original array. ```python def reconstruct(first: int, diff: list[int]) -> list[int]: pass ``` **Example:** ``` Input: first = 3, diff = [2, -1, 4] Output: [3, 5, 4, 8] Explanation: 3 3 + 2 = 5 5 + (-1) = 4 4 + 4 = 8 ``` ## Round 2 - Follow-up Variant Now you are given the array in shuffled order and the difference array in shuffled order, but you are NOT given `original[0]`. Determine if a valid reconstruction exists. If yes, return one valid original array. ```python def can_reconstruct(shuffled: list[int], diff_shuffled: list[int]) -> list[int] | None: pass ``` ## Follow-ups 1. What is the time and space complexity of your reconstruction? 2. In the shuffled variant, how many possible starting values are there to check? 3. How would you handle floating-point differences with precision errors? 4. Extend to 2D: reconstruct a matrix from row and column difference arrays.

## Problem Implement a circular queue (ring buffer) with enqueue and dequeue operations, handling wrap-around indices. ## Likely LeetCode equivalent LC 622 - design-circular-queue ## Tags queue, design, arrays

## Round 1 - Fundamentals Q&A **Operating Systems:** - What is the difference between a process and a thread? - Explain how virtual memory works. What happens on a page fault? - What is a deadlock? State the four necessary conditions. **Networking:** - Walk me through what happens when you type `https://example.com` in a browser and hit Enter. - What is the difference between TCP and UDP? When would you choose UDP? - What does a 3-way handshake accomplish? **Data Structures:** - When would you choose a hash map over a BST? - Explain how a consistent hash ring works. **Concurrency:** - What is a race condition? Give an example. - How does a mutex differ from a semaphore? ## Round 2 - Coding Warm-up Implement a thread-safe counter in Python using a lock. ```python import threading class SafeCounter: def __init__(self): ... def increment(self): ... def value(self) -> int: ... ``` ## Follow-ups 1. How would you detect a deadlock at runtime in a production system? 2. Explain cache coherence in a multi-core CPU. 3. What tradeoffs do you make when choosing between optimistic and pessimistic locking? 4. How does Python's GIL affect your thread-safe counter?

## Problem Group or retrieve favorite songs by some criteria, likely using hash maps or sorting to find most-played or top-rated songs. ## Tags hash_table, arrays, sorting

## Problem Allocate orders to slots or resources optimally, likely a greedy or DP scheduling problem. ## Tags greedy, dynamic_programming, arrays

## Problem Maintain a leaderboard of top orders by volume or priority, likely using a heap or sorted structure for efficient top-k queries. ## Tags heap, sorting, design