Optimize compression for with follow-up
Last updated: April 23, 2026
Quick Overview
Given a string of characters, implement a function to optimize the compression of the string such that consecutive duplicate characters are replaced by a single character followed by the count of its occurrences. The function should return the compressed string, and if the compressed string is not smaller than the original, return the original string instead.
Vercel
April 23, 20268
12
595 solved
Given a string of characters, implement a function to optimize the compression of the string such that consecutive duplicate characters are replaced by a single character followed by the count of its occurrences. The function should return the compressed string, and if the compressed string is not smaller than the original, return the original string instead.
Vercel uses this problem in the Take-home Project to evaluate your algorithmic thinking. They expect you to discuss multiple approaches, analyze trade-offs between them, and implement the optimal solution with clean, readable code.
What the Interviewer Expects
- Identify the correct data structure and algorithm for the problem
- Write clean, bug-free code with proper variable naming
- Analyze time and space complexity correctly
- Handle basic edge cases (empty input, single element)
- Communicate your thought process while coding
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
- Can you solve this iteratively instead of recursively (or vice versa)?
- What happens if the input contains duplicates?
- How would you parallelize this solution?
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Practice DSA ProblemsSample Answer
Problem Analysis
The problem requires us to compress a string by replacing consecutive duplicate characters with a single instance of the character followed by the count of its occurrences. This is a classic applicati...
Approach
- Initialize a pointer
ito traverse the string and a variablecompressedto build the compressed result. - Use a loop to go through the string. For each character, maintain a
countvariable...
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