Oracle Interview Questions
We track 30 interview questions reported from Oracle: 28 in Coding & Leetcode-style Questions, 1 in ML Fundamentals & Algorithms. They average 2.8/5 difficulty — medium for a working engineer — and every one was reported by someone who sat the loop, not written by us. The topics that come up most: array, hashmap, string, design.
Practice these on the problems board →Question mix
- Coding & Leetcode-style Questions28
- ML Fundamentals & Algorithms1
- System Design for ML1
Difficulty
- 2/5 — easy5
- 3/5 — medium25
Asked for SWE (29), Infra (10), MLE (6), RS (1)
Topics Oracle asks about
Reported Oracle questions
ML Coding — Handwritten MHA and Sparse Matmul
3/5Master core machine learning implementation tasks frequently encountered in technical interviews for artificial intelligence roles at Oracle. This challenge requires building foundational neural network components from scratch using fundamental tensor operations, specifically focusing on custom attention mechanisms and optimized sparse matrix multiplication without relying on high-level framework abstractions. Unlock the complete technical walkthrough, architectural insights, and production-ready reference solution by upgrading to a paid subscription.
ML Fundamentals & AlgorithmspytorchnumpytransformerOOD — File Management System
2/5This Oracle coding exercise requires you to build a lightweight in-memory directory management utility. You will implement foundational functions to verify folder existence, generate new directories, and add files while carefully managing tricky edge cases and duplicates. It measures your ability to write clean, robust object-oriented code under test conditions. Unlock the full prompt and expert implementation details with a paid subscription.
Coding & Leetcode-style Questionsoop-designfilesystemhashmapSame N-ary Tree Comparison
2/5This Oracle interview question expands upon traditional binary tree comparison tasks by asking you to evaluate N-ary trees for structural and value equality. You will first tackle the straightforward recursive approach, followed by an advanced iterative follow-up that traverses both hierarchies simultaneously using explicit auxiliary data structures. It serves as an excellent test of your tree traversal mastery and pointer management. The comprehensive breakdown, alongside recursive and iterative model solutions, requires a paid subscription.
Coding & Leetcode-style QuestionstreerecursiondfsNumber of Islands (LC 200)
3/5Evaluating spatial traversal skills is common in technical screenings, highlighted by this Oracle phone-screen question equivalent to a well-known LeetCode problem. The objective requires tallying isolated land formations within a two-dimensional matrix using standard graph exploration techniques while meticulously documenting performance metrics. Candidates must demonstrate fluency in recursive or queue-based traversal patterns alongside precise time and space complexity analysis. Unlock the complete problem guide, step-by-step walkthrough, and production-ready solution by securing a paid subscription today.
Coding & Leetcode-style QuestionsdfsgraphmatrixMerge K Sorted (Key, Value) Lists with Later Override
3/5Reported as an Oracle OCI screening question, this challenge requires combining multiple ordered sequences of key-value pairs while correctly applying precedence rules when duplicate keys occur across different collections. It assesses your ability to adapt multi-way merging algorithms, such as those driven by min-heaps, to incorporate custom conflict-resolution logic based on source indices. You will practice maintaining sorted order while overriding older data with newer updates. Access to the complete solution and detailed explanation requires a subscription.
Coding & Leetcode-style Questionsheaplinked-listmergeCode Reading — CLI Tool Feature Audit
3/5Stepping away from traditional algorithmic puzzles, this code-reading exercise requires you to audit an existing command-line utility codebase against a formal product requirements specification to identify gaps and architectural flaws. Documented as an onsite Oracle interview scenario, it highlights code comprehension, software engineering best practices, and refactoring techniques. Reviewing the complete prompt documents and expert feedback requires an active subscription.
Coding & Leetcode-style Questionscode-readingrefactoringdesign-reviewContainer With Most Water (LC 11)
3/5This classic algorithmic challenge, featured during a phone screen at Oracle, asks you to determine the maximum volume of liquid that can be retained between two vertical barriers within an integer array. Candidates must evaluate pairs of coordinates to maximize the product of their separation and their limiting height efficiently. Discovering the optimal linear-time two-pointer strategy and reviewing the complete model solution requires a subscription.
Coding & Leetcode-style Questionsarraytwo-pointergreedyMaximum Completable Tasks with Prerequisites (Topological)
3/5Reported as an Oracle screening question, this graph-theoretic challenge requires determining the maximum number of milestones you can achieve given strict dependency constraints. Because certain pathways might contain circular dependencies, you must identify valid execution sequences using topological sorting principles. The puzzle evaluates your graph traversal skills and your ability to prune invalid branches efficiently. Unlock the complete problem text, underlying architectural patterns, and verified solution code with a subscription.
Coding & Leetcode-style Questionsgraphtopological-sortbfsOOD — Treatment Frequency Scheduler
3/5Reported from Oracle technical screens, this object-oriented design question requires building a flexible scheduling engine to generate recurring medical treatment schedules within specified timeframes. You must model various recurrence patterns and efficiently compute all valid occurrence timestamps across multiple patients. The task evaluates your ability to design clean class hierarchies and handle complex date and time arithmetic cleanly. Get full access to the complete design patterns and reference solution by subscribing.
Coding & Leetcode-style Questionsoop-designschedulingmathAnagram Word Replacement in Phrases (Find All Anagrams)
3/5Optimize your sliding window techniques with this string-matching puzzle featured in Oracle Health technical screens. This challenge tests your capability to efficiently locate contiguous segments within a larger text that match specific letter permutations, all while avoiding costly brute-force overhead. You will learn how frequency tracking and optimized pointer movement drastically improve runtime performance on restrictive datasets. Unlock the full algorithmic breakdown, performance optimizations, and complete code solution by purchasing a subscription.
Coding & Leetcode-style Questionsstringhashmapsliding-windowFirst-Login Only-Once User Tracker (O(1) Worst-Case)
3/5Prepare for this Oracle interviewing scenario by designing a high-performance data structure that tracks user authentication events. The core challenge requires you to record incoming user logins and instantly query the chronologically first user who has logged in exactly once throughout their lifetime, all while maintaining strict constant time complexity for every operation. This problem tests your expertise in combining hash maps with doubly linked lists or custom index tracking mechanisms. The detailed problem breakdown and expert solution require a subscription.
Coding & Leetcode-style Questionslinked-listhashmapdesignMinimum Sum After K Halvings (Max-Heap)
3/5Examine a numeric optimization problem reported in an Oracle engineering loop, where you must strategically reduce elements using repeated division to achieve the smallest possible total sum. Candidates must determine the optimal sequence of choices under operation limits while handling edge cases efficiently. This question tests your proficiency with priority queues and greedy strategies to avoid performance bottlenecks. Unlock the full problem statement, test cases, and optimal solution code with a subscription.
Coding & Leetcode-style QuestionsheapgreedyarraySimplify Expression by Removing Parentheses
3/5Asked during an onsite interview at Oracle Labs, this string manipulation challenge tests your ability to parse algebraic expressions containing nested parentheses and distribute unary signs across variables. You are required to flatten the expression completely while adhering to mathematical rules for addition and subtraction over symbols. This problem tests stack utilization and careful parsing logic. The complete problem description, test cases, and reference solution require a subscription.
Coding & Leetcode-style QuestionsstringstackparsingTrie-Based Autocomplete
3/5Reported during Oracle interviews, this problem asks you to build a robust predictive text lookup service using a dictionary dataset and prefix queries. Beyond basic retrieval, the evaluation heavily emphasizes clean architecture, requiring a strict separation of concerns between the underlying tree structure and the service logic, with potential follow-ups involving frequency-based ranking. It tests both your data structure design skills and your commitment to maintainable code. The full problem and model solution require a subscription.
Coding & Leetcode-style QuestionstriedfsstringHospital Appointment Booking API
3/5This Oracle interview question requires you to design a robust RESTful API for managing medical appointments across numerous practitioners with fixed daily schedules and time slots. You will need to tackle state management challenges, handle rapid booking requests, and efficiently return the next available opening or an appropriate error response. Unlocking the complete system architecture, API specifications, and working reference solution requires an active platform subscription.
Coding & Leetcode-style Questionsdesigndata-structureconcurrencyCode Review Round (Verbal)
3/5This Oracle screening scenario features a dual-phase assessment combining critical code critique with a conversational system design review based on past professional experience. It evaluates your code-reading acuity, debugging instincts, and ability to communicate architectural decisions effectively without writing traditional algorithmic code. The complete guide and expert evaluation strategies require a subscription.
Coding & Leetcode-style Questionscode-reviewdesign-reviewverbalValid 5-Card Poker Straight
2/5Asked during an Oracle Health screening process, this exercise requires you to evaluate a hand of playing cards to check if they form a valid sequence of consecutive values with flexible handling for face cards and aces. It assesses foundational data manipulation, conditional logic, and mapping techniques within a timed coding environment. Unlock the full prompt and complete code solution by getting a subscription.
Coding & Leetcode-style QuestionsarraysetsimulationVerbal Java / CS-Fundamentals Quiz
3/5Master the essential Java and computer science fundamentals commonly tested during Oracle technical screenings. This prep page focuses on rapid-fire verbal quizzes covering object-oriented design principles, concurrency concepts, and internal data structure mechanisms that interviewers frequently interleave with live coding challenges. Evaluating your theoretical depth helps ensure you can defend architectural choices and handle unexpected follow-up questions seamlessly. Access the full question bank, core concepts, and expert explanations with a subscription.
Coding & Leetcode-style Questionscs-fundamentalsverbalnetworkingCourse Scheduler — Print Path (Simplified)
2/5Featured during a technical screening at Oracle, this simplified dependency resolution task requires candidates to generate an ordered sequence of study modules based on single prerequisite links. The challenge tests your graph traversal capabilities and how well you can map out linear execution orders under strict dependency rules. Interviewers use this scenario to evaluate clean implementation speed and foundational data structure handling within a tight timeframe. Access to the full problem description and the expert-crafted model solution requires an active subscription.
Coding & Leetcode-style Questionsgraphtopological-sorttreeApply List of Operations (Command Pattern)
3/5This reported Oracle Health interview challenge evaluates your ability to structure maintainable code by applying a sequence of modifications to a baseline configuration. Rather than focusing on standard algorithmic puzzles, this exercise tests how well you implement design patterns to handle state transformations and manage execution flows. You will explore how to cleanly execute ordered directives while considering potential optimizations like reordering or consolidation. Access to the comprehensive problem description and optimal architecture requires an active subscription.
Coding & Leetcode-style Questionsoop-designobject-designdesign-patternOOD — Body-Temperature Measurement Classes
3/5In this object-oriented design task reported from Oracle, candidates must build a robust Java class hierarchy to record and analyze patient temperature metrics. Starting from a basic specification, the interviewer progressively introduces new requirements regarding measurement units, different collection methods, and specific clinical fever thresholds. This exercise tests your ability to adapt object models dynamically without relying on complex algorithms. Unlock the complete breakdown, detailed requirements, and reference implementation by subscribing today.
Coding & Leetcode-style Questionsoop-designobject-designSimplified Redis-Like KV / List Store
3/5This system design and implementation task, featured in Oracle screening loops, requires building a lightweight in-memory key-value data store that supports basic scalar assignments alongside collection-based list operations. The exercise tests your ability to design clean class interfaces, manage diverse internal data types, and handle collection modifications efficiently. Access to the full problem requirements and professional model solution requires a subscription.
Coding & Leetcode-style Questionsdata-structurein-memory-databasedesignSystem Design — Event Ingestion + Top-K Aggregation
3/5Scaling a single-server architecture to handle massive request volumes while simultaneously tracking frequent occurrences is a common system design challenge frequently discussed in Oracle interviews. This scenario requires you to transition a basic event-reporting endpoint into a distributed, high-throughput pipeline capable of computing top-K aggregations efficiently in real-time. The evaluation focuses on your ability to address bottlenecks, design data streaming pipelines, and choose appropriate distributed data structures. Gain complete access to the comprehensive problem guide and expert architectural solutions by subscribing.
System Design for MLsystem-designstreamingtop-kLog Parser with Multi-Line Follow-up
3/5This log processing challenge, reported from Oracle interviews, tests a candidate's ability to ingest continuous text streams, parse structured data entries based on timestamps and severity levels, and validate formatting rules. A key follow-up introduces multiline log entries that must be correctly aggregated and associated with their parent record. The task evaluates string manipulation, parsing logic, and edge-case handling. Gain access to the full problem breakdown and expert solution by purchasing a subscription.
Coding & Leetcode-style Questionsstringparsingstate-machineLRU Cache with Expiration (LC 146 + TTL)
3/5This Oracle interview question delves into advanced data structure design, combining the principles of a Least Recently Used (LRU) cache with an additional layer of complexity: time-to-live (TTL) expiration. You'll need to engineer a cache that supports efficient O(1) operations for both retrieval and insertion, while also ensuring that entries automatically become invalid after a specified duration. This problem tests your understanding of hash maps, linked lists, and how to integrate temporal logic into a performant caching mechanism. The full problem and model solution require a subscription.
Coding & Leetcode-style Questionshashmaplinked-listttlSort Array by Parity — Minimum Swaps
3/5This coding interview question, frequently encountered in technical screenings at Oracle, challenges candidates to reorder a collection of integers such that all even numbers precede all odd ones using the fewest possible swaps. This problem evaluates your ability to manipulate arrays efficiently and implement strategic pointer movements from both extremities of the dataset. To successfully solve this challenge, you must minimize operations while adhering strictly to the parity grouping requirement. The complete problem statement, detailed explanations, and optimized model solution require a subscription.
Coding & Leetcode-style Questionstwo-pointerarraygreedyBinary Search — Rightmost Index of Duplicate
2/5This interview question, featured in an Oracle screening session, challenges candidates to locate the final occurrence of a duplicated element within an ordered collection. It evaluates your ability to adapt standard logarithmic search algorithms to handle multiple identical entries efficiently without resorting to linear scans. You will learn how to narrow down boundaries effectively when duplicates are present. Access to the complete problem breakdown and optimal code implementation requires a subscription.
Coding & Leetcode-style Questionsarraybinary-searchMonotone Increasing Digits (LC 738)
3/5Faced during an Oracle coding interview, this algorithmic challenge requires finding the highest valid integer beneath a given threshold where digits follow a strictly non-decreasing sequence. The exercise evaluates greedy optimization techniques, digit manipulation, and edge-case handling under strict constraints. It tests the ability to transform an intuitive pattern into an optimal computational approach. The complete problem statement and verified code implementation are reserved for subscribers.
Coding & Leetcode-style QuestionsgreedymathSet Matrix Zeros (in-place) (LC 73)
3/5Examine a classic matrix manipulation puzzle commonly posed during technical screenings at Oracle, where developers must modify a two-dimensional grid in place. The objective requires setting entire rows and columns to zero whenever a zero cell is encountered, all without allocating supplementary memory structures. Interviewers frequently expand this challenge by introducing non-rectangular data shapes and generalized marker types to test adaptability. Unlocking the full problem description and comprehensive solution demands a subscription.
Coding & Leetcode-style QuestionsarraymatrixhashmapDecode String (k[encoded]) (LC 394)
3/5Featured in an Oracle technical screening, this classic coding problem asks you to process and expand a text sequence governed by nested repetition rules. The task assesses your proficiency with stack-based data structures, string manipulation, and parsing algorithms. You must carefully manage embedded segments and repeat counts to rebuild the original text correctly. Unlock the full problem details and optimal implementation by subscribing to our platform.
Coding & Leetcode-style Questionsstringstackrecursion
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Oracle interview FAQ
- How many Oracle interview questions are available?
- 30 reported Oracle questions, the largest group being Coding & Leetcode-style Questions (28).
- How hard is the Oracle interview?
- Across the questions we track, Oracle averages 2.8 out of 5: 5 at 2/5, 25 at 3/5.
- What topics does Oracle ask about?
- Most often array, hashmap, string, design, oop-design.