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Implement string reduction and time map | Grammarly Interview Question

Q: Implement string reduction and time map

This question evaluates skills in string-processing algorithms and time-based data structure design, measuring competency in correctness, efficiency, and handling repeated pattern removals and temporal key-value retrieval.

In a coding interview, you are asked to solve two algorithm problems.

String reduction with adjacent duplicates
- Basic version: Given a string s , repeatedly remove any adjacent pair of equal characters until no such pair remains. Return the final string.
- Follow-up: Given a string s and an integer k , repeatedly remove any group of k adjacent equal characters until no more removals are possible. Return the final string.
- Example follow-up: if s = "deeedbbcccbdaa" and k = 3 , the answer is "aa" .
Time-based key-value store
- Design a data structure that supports:
  - set(key, value, timestamp) : store a value for a key at a given timestamp.
  - get(key, timestamp) : return the value associated with the largest timestamp less than or equal to the given timestamp for that key. If no such timestamp exists, return an empty string.
- Assume timestamps passed to set are strictly increasing for each key.
- Implement both operations efficiently.

Write working code for both problems and explain the time and space complexity of your approach.

In a coding interview, you are asked to solve two algorithm problems.

String reduction with adjacent duplicates
- Basic version: Given a string s , repeatedly remove any adjacent pair of equal characters until no such pair remains. Return the final string.
- Follow-up: Given a string s and an integer k , repeatedly remove any group of k adjacent equal characters until no more removals are possible. Return the final string.
- Example follow-up: if s = "deeedbbcccbdaa" and k = 3 , the answer is "aa" .
Time-based key-value store
- Design a data structure that supports:
  - set(key, value, timestamp) : store a value for a key at a given timestamp.
  - get(key, timestamp) : return the value associated with the largest timestamp less than or equal to the given timestamp for that key. If no such timestamp exists, return an empty string.
- Assume timestamps passed to set are strictly increasing for each key.
- Implement both operations efficiently.

Write working code for both problems and explain the time and space complexity of your approach.

Implement string reduction and time map

Quick Overview

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Implement string reduction and time map

Quick Overview

Submit Your Answer to Earn 20XP