Google

PART 1: ALGORITHMIC PROBLEM - DOCUMENT SNIPPET EXTRACTOR BASE PROBLEM You are building a search engine feature. You are given a large document represented as a string 'D', and an array of target characters or keywords 'K'. Task: Find the shortest continuous substring (snippet) within 'D' that contains every element from 'K' at least once. If no such substring exists, return an empty string. FOLLOW-UP 1 The search engine requirements change. Now, the elements in 'K' must appear in the exact chronological order they are given in the array to form a valid snippet. Other characters can still appear between them. Task: How would you modify your algorithm to find the shortest continuous substring that contains all elements of 'K' in the specified sequence? What is the new time and space complexity? FOLLOW-UP 2 The document 'D' is no longer a static file but an infinite, live stream of text data (e.g., a continuous server log). You cannot store the entire document in memory. Task: Design an algorithm to process this stream character-by-character. How do you maintain and update the shortest valid window seen so far without running out of memory? What data structures are necessary to drop old, useless characters while keeping track of the required ones? PART 2: AI DISCUSSION & TERMINOLOGY Practical Application & Product Safety: If you were integrating an AI chatbot into a bank's customer service platform, how would you design the system to handle or detect "hallucinations" so it doesn't confidently give a customer incorrect policy or account information? General Knowledge: What is RLHF (Reinforcement Learning from Human Feedback) and why was it a critical step in evolving raw AI models into helpful, conversational assistants? Basic Terminologies (Briefly explain the following concepts): Temperature: A parameter setting in AI models that controls the randomness of the generated text. A low temperature (e.g., 0.1) makes the output highly predictable and focused, while a high temperature (e.g., 0.9) makes it more diverse and creative. System Prompt (or System Message): Hidden, foundational instructions given to an AI model by the developer before the user interacts with it. It dictates the AI's persona, rules, and restrictions (e.g., "You are a math tutor. Do not give the final answer, only hints."). Time to First Token (TTFT): A key metric in AI performance. It measures the latency or delay from the moment a user submits a prompt to the exact moment the AI generates the very first piece of its response. Vector Database: A specialized type of database designed to store and quickly search through "embeddings" (mathematical representations of text). It is heavily used to instantly find relevant documents for an AI to read before it answers a user's question.