Optimize compression for with follow-up
Last updated: December 15, 2025
Quick Overview
Given a string of text, optimize its compression by replacing consecutive repeated characters with a single character followed by the count of repetitions (e.g., "aaabb" becomes "a3b2"). Your solution should handle edge cases such as empty strings and ensure that the output is the shortest possible compressed version. Return the compressed string as the output.
TikTok
December 15, 2025281
12
2,063 solved
Given a string of text, optimize its compression by replacing consecutive repeated characters with a single character followed by the count of repetitions (e.g., "aaabb" becomes "a3b2"). Your solution should handle edge cases such as empty strings and ensure that the output is the shortest possible compressed version. Return the compressed string as the output.
This coding problem is frequently asked during Onsite at TikTok. The interviewer is testing your ability to translate a problem into clean, working code while discussing time and space complexity. TikTok expects candidates to write production-quality code, not just solve the puzzle.
What the Interviewer Expects
- Quickly identify the optimal approach and its theoretical basis
- Handle complex algorithm design with multiple interacting components
- Write concise, elegant code under time pressure
- Prove correctness of your approach and discuss alternative solutions
- Optimize beyond the obvious: discuss constant factor improvements
- Address follow-up variations and explain how the solution generalizes
Key Topics to Cover
How to Approach This
- Clarify input constraints and edge cases before writing code.
- Walk through your approach verbally and confirm with the interviewer before coding.
- Start with a brute force solution, then optimize. Mention time and space complexity.
- Test your solution with examples, including edge cases like empty input or duplicates.
- Consider common patterns: sliding window, two pointers, hash map, BFS/DFS, dynamic programming.
Possible Follow-up Questions
- How would you test this solution thoroughly?
- How would you parallelize this solution?
- What if the input doesn't fit in memory?
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Practice DSA ProblemsSample Answer
Problem Analysis
The problem requires us to compress a given string by encoding consecutive repeated characters into a single character followed by the count of repetitions. This problem can be efficiently solved usin...
Approach
- Initialize Pointers and Variables: Start with two pointers:
ifor iterating through the original string andjfor building the compressed string. Also, initialize an empty listresultto ...
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