A systematic approach to mastering the Blind 75 problem set through deep understanding, not memorization.
This repository documents my 45-day journey through the Blind 75 LeetCode problems. Each solution includes detailed comments explaining the thought process, pattern recognition, and time/space complexity analysis.
The goal is not to solve problems quickly, but to understand them deeply enough to solve similar problems independently.
For each problem, I follow this method:
- Attempt the problem without assistance for 20 minutes
- If stuck, study the solution and understand the underlying pattern
- Close all references and rewrite the solution from memory
- Add comments explaining each section of the code
- Repeat until I can solve it cold
When multiple approaches exist, both solutions are included in the same file with explanations of the tradeoffs.
blind-75-leetcode/
├── containsDuplicate.py
├── twoSum.py
├── validParentheses.py
└── wordSearch-ii.py
| Pattern | Key Insight |
|---|---|
| HashMap Lookup | Store seen elements for O(1) lookup |
| Stack for Matching | LIFO structure for nested/paired elements |
| Day | Date | Problems Solved |
|---|---|---|
| 1 | Jan 17, 2026 | Valid Parentheses, Contains Duplicate, Two Sum |
Started: January 17, 2026 Target Completion: February 28, 2026