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This question is commonly asked for Software Engineer candidates at Dropbox during technical interviews.

Build a hit/miss word guessing game | Dropbox Interview Question

Q: Build a hit/miss word guessing game

This question evaluates implementation skills in managing stateful systems and data structures for pattern matching, as well as algorithmic and adversarial reasoning about information gain and search strategies when the secret can change.

Two players play a word guessing game.

Player A chooses a secret word .
Player B repeatedly guesses single letters .
After each guess, the game reports:
- hit if the secret word contains the guessed letter, and all occurrences of that letter are revealed in the current pattern
- miss otherwise, and the letter is added to a misses list

The interviewer will provide an example interaction to confirm behavior.

Part 1 — Implement the game engine

Design and implement data structures and functions to support:

Initializing a game with a secret word
Processing a guessed letter and returning updated state
Tracking revealed letters (e.g., pattern like _ _ a _ a )
Tracking missed letters (in insertion order)

Inputs/Outputs (one possible shape)

Input: secretWord , then a sequence of guessed letters
Output after each guess: { result: "hit"|"miss", pattern, misses }

Part 2 (Follow-up) — Secret word may change mid-game

Now Player A is allowed to change the secret word during the game, as long as it remains consistent with all previous responses (hits/misses and revealed pattern).

Player B wants to minimize the number of guesses needed to fully determine the word.

Discuss an approach and write high-level pseudocode for the strategy Player B should use.

Assumptions you may make (state clearly):

There is a known dictionary/set of candidate words of the same length.
Only letter guesses are allowed (no full-word guesses), unless you explicitly add that rule.
Letters may or may not be repeated in guesses (specify behavior).

Part 1 — Implement the game engine

Design and implement data structures and functions to support:

Initializing a game with a secret word

Processing a guessed letter and returning updated state

Tracking revealed letters (e.g., pattern like _ _ a _ a )

Tracking missed letters (in insertion order)

Inputs/Outputs (one possible shape)

Input: secretWord , then a sequence of guessed letters

Output after each guess: { result: "hit"|"miss", pattern, misses }

Part 2 (Follow-up) — Secret word may change mid-game

Now Player A is allowed to change the secret word during the game, as long as it remains consistent with all previous responses (hits/misses and revealed pattern).

Player B wants to minimize the number of guesses needed to fully determine the word.

Discuss an approach and write high-level pseudocode for the strategy Player B should use.

Assumptions you may make (state clearly):

There is a known dictionary/set of candidate words of the same length.

Only letter guesses are allowed (no full-word guesses), unless you explicitly add that rule.

Letters may or may not be repeated in guesses (specify behavior).

Build a hit/miss word guessing game

Quick Overview

Part 1 — Implement the game engine

Inputs/Outputs (one possible shape)

Part 2 (Follow-up) — Secret word may change mid-game

Submit Your Answer to Earn 20XP

Build a hit/miss word guessing game

Quick Overview

Part 1 — Implement the game engine

Inputs/Outputs (one possible shape)

Part 2 (Follow-up) — Secret word may change mid-game

Submit Your Answer to Earn 20XP