Coding Interview Preparation

A systematic guide to mastering coding interviews — from foundational data structures to advanced algorithmic patterns, with solutions and best practices.

What This Knowledge Base Covers

This resource is designed to help you prepare for technical coding interviews by building a strong foundation in data structures and algorithms. Whether you're preparing for FAANG companies or strengthening your problem-solving skills, this guide provides structured learning paths and practical solutions.

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Learning Paths

📦 Fundamentals

Master the core building blocks:

• Arrays — Indexing, slicing, searching, sorting
• Linked Lists — Traversal, insertion, deletion, reversal
• Stacks & Queues — LIFO/FIFO operations, applications
• Sorting Algorithms — QuickSort, MergeSort, HeapSort, and more

🎯 Core Patterns

Learn problem-solving techniques that apply across many problems:

• Two Pointers — Converging/diverging approaches for arrays
• Sliding Window — Optimal substring/subarray problems
• Prefix Sum — Range queries and cumulative calculations
• Binary Search — Log-time searching and decision problems
• Matrices — 2D array traversal and manipulation

🌲 Trees & Graphs

Understand hierarchical and network structures:

• Trees — DFS, BFS, tree properties, path problems
• BFS — Level-order traversal, shortest paths
• DFS — Depth-first traversal, backtracking
• Graphs — Representations, connectivity, cycles
• Union-Find — Disjoint set operations, connectivity
• Trie — Prefix trees for string problems

⚡ Advanced Patterns

Master complex problem-solving techniques:

• Heap — Priority queues, k-largest elements, scheduling
• Backtracking — Permutations, combinations, constraint satisfaction
• Dynamic Programming — Optimal substructure, memoization, DP tables
• Greedy — Optimal choices, interval scheduling, activity selection
• Bit Manipulation — Bitwise operations, binary tricks
• Monotonic Stack — Next/previous greater/smaller elements
• Intervals — Merging, overlapping, scheduling problems

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How to Use This Guide

Step	Action
1	Start with Fundamentals if you're new to competitive programming
2	Progress through Core Patterns to build problem-solving intuition
3	Study Trees & Graphs for hierarchical data structure problems
4	Master Advanced Patterns for complex, multi-step problems
5	Practice repeatedly—consistency beats memorization

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Interview Preparation Tips

✅ Understand the Problem — Read carefully, ask clarifying questions
✅ Analyze Complexity — Time and space — aim for optimal solutions
✅ Code Clear & Clean — Readable, well-structured code with comments
✅ Test Thoroughly — Edge cases, empty inputs, large inputs
✅ Explain Your Approach — Communication is key in interviews

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Resources Inside

Each section includes:

• Problem explanations with real-world context
• Multiple solution approaches from brute force to optimal
• Time & space complexity analysis
• Code implementations in Java/Python
• Common pitfalls and how to avoid them
• Interview tips and follow-up questions

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Recommended Study Order

Week 1-2: Arrays, Strings, Linked Lists
Week 3-4: Stacks, Queues, Basic Sorting
Week 5-6: Two Pointers, Sliding Window, Binary Search
Week 7-8: Trees, BFS/DFS, Backtracking
Week 9-10: Graphs, Union-Find, DP Intro
Week 11-12: Advanced DP, Greedy, Bit Manipulation

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Practice Platforms

Popular coding platforms for reinforcement:

• LeetCode — 3000+ problems, company-tagged
• HackerRank — Structured learning tracks
• AlgoExpert — Video solutions and explanations
• Neetcode — Curated 150 problems with patterns

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Happy coding! 🚀