Coding Interview: From Zero to Hero

This is a pattern-first, interview-focused guide for mastering coding interviews at FAANG companies (Google, Meta, Amazon, Apple, Microsoft).

Based on the legendary Grind 75 and Blind 75 - curated by engineers who've been through it.

TL;DR: What's the Secret?

Don't memorize 500 LeetCode problems. Learn 15-20 patterns that cover 90% of interview questions.

Pattern Recognition > Brute Force Grinding

Who Should Use This Guide?

• You have an interview in 2-12 weeks
• You're rusty on DSA but know the basics
• You want maximum ROI on limited study time
• You've been grinding but can't see patterns

The Anti-Grind Philosophy

Most people fail coding interviews not because they're bad at coding, but because:

1. ❌ Random grinding - doing LeetCode without patterns
2. ❌ Passive learning - watching solutions without implementing
3. ❌ Skipping fundamentals - jumping to hard problems
4. ❌ No time management - spending 2 hours on one problem

This guide fixes all of that.

Learning Path

Course Structure

Part 1: Foundations (Know Your Tools)

Chapter	Topic	Why It Matters
01	Data Structures Cheatsheet	Know when to use what - O(1) vs O(n) matters
02	Big O Notation	First thing interviewers evaluate
03	Interview Best Practices	The meta-game: how to communicate

Part 2: Core Patterns (The Grind 75)

These 15 patterns cover 90% of questions.

Pattern	Key Technique	Example Problems
04	Two Pointers	Opposite/same direction
05	Sliding Window	Subarray/substring
06	Binary Search	Search space reduction
07	BFS/DFS	Tree/graph traversal
08	Backtracking	Choice → Explore → Unchoose
09	Dynamic Programming	Overlapping subproblems
10	Greedy	Local optimal → Global
11	Stack/Queue	LIFO/FIFO processing
12	Heap/Priority Queue	Top K, K-way merge
13	HashMap/Set	O(1) lookup
14	Linked List	Pointer manipulation
15	Tree Patterns	Recursive thinking
16	Graph Patterns	BFS/DFS + Union Find
17	Intervals	Sort + merge/overlap
18	Bit Manipulation	XOR, AND, shifts

Part 3: Advanced Topics

Chapter	Topic	When You Need It
19	Trie (Prefix Tree)	Autocomplete, word search
20	Monotonic Stack	Next greater element
21	Union-Find	Disjoint sets, connected components
22	Topological Sort	Build order, prerequisites
23	Segment Tree	Range queries (rare in interviews)

Part 4: Interview Mastery

Chapter	Topic	Purpose
24	Study Plans	2-week, 4-week, 12-week roadmaps
25	Mock Interview Guide	How to practice effectively
26	Company-Specific Tips	Google, Meta, Amazon patterns
27	Quiz Bank	Test your pattern recognition

The Grind 75 List (Quick Reference)

Week 1: Easy (Build Confidence)

#	Problem	Pattern	Time
1	Two Sum	HashMap	15 min
2	Valid Parentheses	Stack	20 min
3	Merge Two Sorted Lists	Linked List	20 min
4	Best Time to Buy/Sell Stock	Sliding Window	20 min
5	Valid Palindrome	Two Pointers	15 min
6	Invert Binary Tree	Tree DFS	15 min
7	Valid Anagram	HashMap	15 min
8	Binary Search	Binary Search	15 min
9	Flood Fill	DFS/BFS	20 min
10	Lowest Common Ancestor	Tree	25 min

Week 2: Medium (Core Patterns)

#	Problem	Pattern	Time
11	Balanced Binary Tree	Tree DFS	15 min
12	Linked List Cycle	Two Pointers	20 min
13	Implement Queue using Stacks	Stack	20 min
14	First Bad Version	Binary Search	20 min
15	Ransom Note	HashMap	15 min
16	Climbing Stairs	DP	20 min
17	Longest Palindrome	HashMap	20 min
18	Reverse Linked List	Linked List	20 min
19	Majority Element	Boyer-Moore	20 min
20	Add Binary	Math	15 min

Weeks 3-8: See Full List in Study Plans

Pattern Recognition Framework

When you see a problem, ask yourself:

What Makes This Guide Different?

✅ Pattern-first - Learn why solutions work, not just what they are
✅ Visual mnemonics - Remember patterns with diagrams
✅ Time-boxed - Know when to move on (15/20/30 min limits)
✅ Difficulty ramp - Easy → Medium → Hard progression
✅ Interview-focused - What FAANG actually asks
✅ Active learning - Quiz yourself, don't just read

The 45-Minute Interview Framework

Most coding interviews are 45 minutes. Here's how to use them:

Phase	Time	What to Do
Understand	5 min	Clarify, examples, edge cases
Plan	5 min	Pattern identification, approach
Code	20 min	Clean, modular implementation
Test	10 min	Walk through, edge cases
Optimize	5 min	Time/space complexity, improvements

Interview Tip

Talk out loud the entire time. Interviewers want to see your thought process, not just the final answer.

Quick Links

• Start Learning: Data Structures →
• Jump to Patterns: Two Pointers →
• Get a Study Plan →
• Test Yourself: Quiz Bank →

Prerequisites

Minimum:

• Basic programming (loops, functions, classes)
• Know what arrays, lists, trees are (even if rusty)
• Can write code in at least one language

Ideal:

• Solved 10-20 LeetCode problems before
• Familiar with recursion
• Know basic Big O (O(1), O(n), O(n²))

Time Investment

Plan	Time/Day	Duration	Best For
Sprint	3-4 hours	2 weeks	Interview in 2 weeks
Standard	2 hours	4-6 weeks	Interview in 1-2 months
Deep	1-2 hours	8-12 weeks	Career preparation

Let's Get Started

Ready to crack the coding interview? Start with:

1. Data Structures Cheatsheet - Know your tools
2. Two Pointers Pattern - The gateway pattern
3. Study Plans - Pick your timeline

Good luck! 🚀

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Based on Tech Interview Handbook by Yangshun Tay - Curated by engineers who've interviewed at Google, Meta, and more.