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Design a Power Plant Electricity Allocator
Design a class-level system modeling a power plant that distributes electricity to multiple neighbourhoods, each with a stated demand, subject to the plant's total capacity.
1. Problem Statement
Design a reusable deck of cards and a single-round game of Blackjack on top of it. Cover cards, the deck's shuffle and deal, hand scoring (including aces that can count as 1 or 11), the player and dealer turns, and how a round is settled. Start by clarifying scope and the core objects.
2. Live Coding Format
Work in the provided coding workspace while explaining your decisions to the live interviewer. Validation may use inline tests, examples, comments, or a verbal walkthrough.
3. Key Focus Areas
- 1Card/Suit/Rank value objects and Deck shuffle/deal
- 2Hand scoring with flexible ace values and blackjack detection
- 3Round lifecycle: deal, hit/stand, dealer policy, settle
- 4Configurable dealer policy and optional betting value object
4. What Strong Candidates Should Demonstrate
- Model Card, Suit, Rank, and Deck as a reusable, well-encapsulated component.
- Compute blackjack hand values correctly with flexible ace handling.
- Separate deck/card mechanics from game rules and dealer policy.
- Model the round lifecycle and terminal outcomes (blackjack, bust, win/lose/push).
Want interactive feedback?
Practice this problem in the live coding workspace while the interviewer probes your clarification, implementation, trade-offs, and validation.
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Object-Oriented DesignDomain ModelingGame ModelingValue Objects
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Design a Car Rental System
Design a car rental domain model covering vehicle categories and vehicles, branches, customers and drivers, a rental date range, rate-based quotes, category reservations, vehicle assignment at pickup, and return inspection with extra charges — without overbooking a category or renting one vehicle for overlapping periods.
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Design a Group Expense-Splitting Ledger
Design a system where users form groups, log shared expenses split equally, by exact amounts, or by percentage, maintain pairwise balances, and settle debts.
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Design a Hotel Management System
Design a hotel domain model covering room types and rooms, guests, a half-open date-range value object, the reservation lifecycle, room assignment, check-in/out, and a charges folio, while preventing overbooking of a room type and overlapping stays on the same room.