 Explain how a hash map handles collisions, and compare chaining versus open addressing. Discuss the trade-offs in terms of lookup performance, insertion speed, memory usage, cache locality, and implementation complexity. Include examples of situations where one strategy is generally preferred over the other and explain how load factor affects performance as the table grows.
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 Write a Python function that merges two sorted lists into one sorted list without using `sorted()` or any external libraries. Explain the time and space complexity of your solution, discuss edge cases such as empty inputs and duplicate values, and describe why your implementation is optimal for already sorted inputs.
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 Summarize the major causes of the 2008 global financial crisis in three concise paragraphs. Cover the housing bubble, subprime mortgage lending, financial derivatives, excessive leverage, regulatory failures, and the resulting banking crisis. End with two key lessons that governments and financial institutions learned afterward.
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 You are a senior backend engineer reviewing an authentication design. The proposal stores user session tokens in `localStorage` for convenience. Explain the security risks, including XSS attacks, token theft, and session hijacking. Recommend a more secure architecture using cookies or alternative mechanisms and explain why your approach is safer.
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 Design a URL shortening service similar to Bitly. Describe the major system components, API endpoints, database schema, key generation strategy, caching layer, analytics collection, scalability considerations, and potential bottlenecks. Explain how the system would handle billions of shortened URLs while maintaining low latency and high availability.
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 Review the following database design conceptually: customer information, orders, products, and payments are stored in a single table with repeated fields. Identify normalization issues, explain the drawbacks of this approach, and propose an improved relational schema that supports efficient querying, updates, and long-term maintenance.
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 Explain how a distributed cache such as Redis improves application performance. Discuss common caching strategies including cache-aside, write-through, write-back, and write-around. Compare their advantages, disadvantages, consistency implications, and appropriate use cases in modern web applications handling millions of requests.
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 A REST API experiences increasing latency during peak traffic even though CPU utilization remains below fifty percent. Describe a systematic debugging process, including database profiling, network latency, connection pooling, thread utilization, lock contention, caching effectiveness, and request tracing. Explain how you would identify and verify the root cause.
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 Write a JavaScript function that limits the execution rate of an event handler using debouncing. Explain how it differs from throttling, provide practical examples for search boxes and scroll events, and discuss situations where each approach improves responsiveness and reduces unnecessary computations.
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 Summarize the transformer architecture used in modern large language models. Explain embeddings, positional encoding, self-attention, multi-head attention, feed-forward layers, residual connections, and normalization. Describe why transformers outperform recurrent neural networks on many natural language processing tasks and mention one important limitation.
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 You are reviewing a pull request that introduces asynchronous processing using message queues. Explain the advantages of decoupling services, improving reliability, handling retries, supporting dead-letter queues, and increasing scalability. Also identify potential operational challenges and recommend best practices for monitoring and observability.
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 Describe the differences between SQL and NoSQL databases. Compare their consistency models, schema flexibility, scaling approaches, query capabilities, transaction support, and typical use cases. Recommend which database type would be appropriate for an e-commerce platform, an analytics pipeline, and a social networking application.
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 Explain how HTTPS secures communication over the internet. Cover TLS handshakes, certificate validation, symmetric and asymmetric encryption, key exchange, and message integrity. Describe what happens when a browser encounters an invalid certificate and explain the potential security risks of ignoring certificate warnings.
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 Write a Python implementation of an LRU cache using a hash map and a doubly linked list. Explain why both data structures are necessary, analyze the complexity of each operation, and discuss alternative implementations that trade simplicity for performance or memory efficiency.
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 Imagine you are the technical lead responsible for migrating a large monolithic application into microservices. Describe how you would identify service boundaries, plan incremental migration, ensure backward compatibility, manage shared data, monitor distributed systems, and reduce operational risks during the transition.
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 Summarize the concept of vector databases and explain why they are widely used in retrieval-augmented generation systems. Compare vector similarity search with traditional keyword search, describe the embedding generation process, and discuss common indexing techniques such as HNSW and IVF for efficient nearest-neighbor retrieval.
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 Review the idea of deploying machine learning inference workloads on GPU spot instances in the cloud. Discuss the cost benefits, interruption risks, checkpointing strategies, automatic recovery mechanisms, workload suitability, and monitoring requirements needed to operate such a system reliably in production environments.
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 Explain how Kubernetes manages application deployments. Describe pods, deployments, replica sets, services, config maps, secrets, rolling updates, health checks, and autoscaling. Include an overview of how Kubernetes responds when a container crashes unexpectedly and how it maintains the desired application state.
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 A software team wants to improve CI/CD reliability. Propose a pipeline that includes automated testing, linting, security scanning, artifact creation, staged deployments, rollback support, and production monitoring. Explain how each stage contributes to software quality and reduces the likelihood of deployment failures.
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Compare synchronous and asynchronous programming models in backend systems. Explain how blocking and non-blocking operations affect throughput, latency, and resource utilization. Provide examples of workloads that benefit from asynchronous execution and discuss situations where a synchronous design remains the simpler and more appropriate choice.
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