← Uber Interview Insights

Uber·Software Engineer·Technical Phone Screen·Intermediate

Intermediate
Apr 2026

Summary

Uber SWE coding round, one main problem with a follow-up on data structures. They also made me write my own test cases which I wasn't fully prepared for.

Questions Asked (2)

Q1

Design a system to schedule meetings, then optimize it using an appropriate data structure.

Algorithms & Data StructuresTechnical Trade-offs
Author's notes

Started fine but didn't reach for a TreeMap on my own.

Create a free account to read the full note

AI HintsAI Generated

Suggested Approach

Start by clarifying requirements (e.g., number of users, meeting duration, conflict resolution) and outlining a basic scheduling system with a list of meetings. Then identify inefficiencies (e.g., O(n) conflict checks) and propose an optimized data structure like an interval tree or segment tree to achieve O(log n) operations.

Pro tip: Emphasize trade-offs: interval trees offer fast queries but are complex, while sorted lists with binary search are simpler but slower for updates. Discuss how Uber's scale (millions of rides/drivers) demands efficient conflict detection and dynamic updates.

1. Clarify Requirements

Ask about scale (number of meetings/users), meeting attributes (start/end, participants), and operations (add, cancel, check availability). This shows you avoid assumptions and design for real needs.

2. Design Basic System

Propose a simple approach: store meetings in a list, check conflicts by iterating. Analyze time complexity (O(n) per operation) and note it's inefficient for large n.

3. Identify Optimization Needs

Highlight bottlenecks: frequent conflict checks and insertions. State the goal: reduce time complexity for add, delete, and query operations.

4. Choose Data Structure

Propose an interval tree (or segment tree) to store intervals, enabling O(log n) insertion, deletion, and overlap queries. Explain how it works and why it fits.

5. Discuss Trade-offs and Extensions

Compare with alternatives (e.g., sorted list + binary search, hash maps). Mention scalability, concurrency, and distributed considerations for Uber's context.

Key Points to Mention

  • Interval tree or segment tree for efficient interval overlap queries
  • Time complexity analysis: O(n) naive vs O(log n) optimized
  • Handling dynamic updates (insertions/deletions) and concurrency
  • Trade-offs: simplicity vs performance, memory overhead
  • Scalability to millions of users/meetings (Uber's scale)
  • Potential use of priority queues or balanced BSTs for specific operations

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

Q2

Write your own test cases for the meeting scheduler and walk through edge cases.

Algorithms & Data Structures
Author's notes

Caught me a bit flat-footed.

Create a free account to read the full note

AI HintsAI Generated

Suggested Approach

Start by clarifying the meeting scheduler's requirements and constraints, then systematically design test cases covering normal, boundary, and edge scenarios. Walk through each edge case, explaining the expected behavior and why it matters, while considering time and space complexity implications.

Pro tip: Demonstrate a structured testing mindset by categorizing cases (e.g., input validation, scheduling logic, concurrency) and prioritizing based on risk and likelihood. Mention how you would automate these tests and integrate them into CI/CD for continuous validation.

1. Clarify Requirements and Assumptions

Ask questions to understand the scheduler's functionality, input/output format, constraints (e.g., time zones, max meetings), and expected behavior. State any assumptions you make.

2. Identify Test Categories

Break down testing into categories: functional (normal cases), boundary (limits), edge (unusual inputs), and non-functional (performance, concurrency).

3. Design Specific Test Cases

For each category, list concrete test cases with input data and expected output. Include cases like empty input, overlapping meetings, back-to-back meetings, and invalid time ranges.

4. Walk Through Edge Cases

Select the most critical edge cases and explain step-by-step how the scheduler should handle them, including any error handling or special logic.

5. Discuss Complexity and Improvements

Analyze the time and space complexity of the scheduler for the test cases, and suggest potential optimizations or additional tests for robustness.

Key Points to Mention

  • Boundary conditions: meetings exactly at start/end of day, zero-duration meetings, maximum number of meetings.
  • Overlapping and conflicting meetings: detection and resolution strategies (e.g., reject, merge, or suggest alternatives).
  • Invalid inputs: end time before start time, malformed time strings, null values, and out-of-range values.
  • Concurrency: simultaneous requests to schedule meetings, race conditions, and thread safety.
  • Time zone and daylight saving time handling: ensuring correct scheduling across zones.
  • Performance: scalability with large number of meetings, efficient data structures (e.g., interval trees, priority queues).

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