Design the snake game
PremiumMachine codingEasy
- Deque
- Grid collision
- Game loop
Quick answer
This machine coding interview question asks you to design the snake game. Aim for a design that meets its requirements at the stated scale, then explain its main components, data flow and trade-offs. Interviewers want to see how you scope the problem, size it and defend each choice.
The problem
Build the Snake game as a code engine: a snake moves one cell per tick on a grid, grows when it eats food and dies when it hits a wall or itself. The hard parts are O(1) collision checks, the tail-cell rule and making random food placement testable.
What must the snake game do?
- Create: new SnakeGame(width, height, foodSource) starts a snake of length 3 at (2,0), (1,0), (0,0) moving RIGHT. x grows to the right and y grows downward.
- Tick: tick() moves the head one cell and returns MOVED, ATE, DIED or WON. Eating adds 1 to the score, grows the snake by one cell and places new food on a free cell.
How well must it do it?
- O(1) per tick: A tick runs in constant time apart from food placement; collision checks never scan the whole body.
- Deterministic tests: Food comes from an injected source: a seeded random picker or a scripted list of cells.
What scale should you design for?
Use these numbers in your estimates.
The scale numbers unlock with this questionUnlock
Key concepts
- Deque
- Grid collision
- Game loop
- Hash set
- Seeded random
- Unit testing
How you’ll practise
- Requirements
- Entities and interfaces
- Core implementation
- Edge cases and tests
- Extensions
- Wrap-up
Lala, personalized to you, gives a hint when you ask and reviews your design when you are ready.
What do interviewers look for?
In any machine coding design round.
- Clarifies the requirements before drawing anything
- Uses a few numbers that actually change the design
- Draws a clear path from the client to storage
- Picks storage and caching with reasons, not by habit
- Explains what breaks first under load and how to fix it
- States trade-offs openly instead of claiming a perfect design
Questions people ask about this interview question
- Which design type is this question?
- It is a machine coding question. You design the snake game and explain your choices the way you would in an interview.
- Is this question asked at entry level?
- It is marked Easy, so it suits engineers who are new to machine coding interviews. It is also a good warm-up before harder questions.
- What should I cover first?
- Start with the requirements: what the system must do, how well it must do it and which numbers change the design. Agree on scope with the interviewer before you design anything.
- Can I practise it for free?
- It is a premium question. Sign up and unlock it once for 10 credits; it then stays unlocked. When you finish, Lala, your personalized AI mentor, can review your design for 30 credits.
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Updated · Written by the SevyDevy team