Blind 75 — Senior Java Edition

The Blind 75 is a curated list of 75 LeetCode problems by Yangshun Tay (2018). Mastering these gives you the recurring patterns behind 90% of FAANG interview questions.

Directory Structure

Each subcategory contains:

• pattern-guide.md — how to identify problems in that category, decision tree, templates, and the curated problem list.
• problems/ — individual .md files per problem with brute force + optimal Java solutions, dry runs, and complexity analysis.

15-Blind-75/
├── pattern-guide.md                    ← master Blind-75 overview
├── interview-tips-and-strategies.md
├── README.md                           ← this file
├── Array/              pattern-guide.md + 10 problems
├── Binary/             pattern-guide.md +  5 problems
├── Dynamic-Programming/pattern-guide.md + 11 problems
├── Graph/              pattern-guide.md +  8 problems
├── Heap/               pattern-guide.md +  3 problems
├── Interval/           pattern-guide.md +  4 problems
├── Linked-List/        pattern-guide.md +  6 problems
├── Matrix/             pattern-guide.md +  4 problems
├── String/             pattern-guide.md + 10 problems
├── Tree/               pattern-guide.md + 11 problems
└── Trie/               pattern-guide.md +  3 problems

Total: 75 problems across 11 categories.

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How to Use Each Sub-Pattern Guide

Open <Category>/pattern-guide.md for:

1. Interview Triggers — keywords that say “this is a Category X problem”
2. Decision Tree — drill down to the right sub-pattern within the category
3. Reusable Templates — Java code you can adapt verbatim
4. Bread & Butter vs FAANG Aha! lists — what to drill first vs save for last
5. Java Implementation Tips — language-specific edges (HashSet.add returns boolean, >>> for unsigned shift, etc.)

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Recommended Study Order

Order	Category	Why study here
1	Array	Foundations — HashMap, two pointers
2	String	Reinforces sliding window & HashMap
3	Linked List	Pointer mastery
4	Tree	Recursion / DFS / BFS
5	Graph	Extends tree thinking to networks
6	Binary	Quick wins with bit tricks
7	Matrix	2-D traversal
8	Interval	Sort-and-merge mindset
9	Heap	Priority-queue use cases
10	Trie	Advanced string matching
11	Dynamic Programming	Save for last — uses everything

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Difficulty Distribution

Difficulty	Count	% of Total
Easy	17	23%
Medium	49	65%
Hard	9	12%

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Cross-Reference with Pattern Directories

Many Blind 75 problems are also covered in the numbered pattern directories 00-Foundations/ through 16-Graph-Patterns/. See the Cross-Reference section in pattern-guide.md for the full mapping. The numbered directories teach a pattern; the Blind-75 directories arrange the same problems by category.

Use the numbered directories when you’re learning a pattern. Use the Blind-75 directories when you’re drilling specific problems.