75 Problem-Solving Patterns in Python, Java, and JavaScript

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Stop memorizing hundreds of problems. Learn the patterns behind them.

Most coding interview problems are variations of a much smaller set of ideas. This book teaches 75 problem-solving patterns — how to recognize each one from the wording of a problem, why it works, and how to implement it cleanly in Python, Java, and JavaScript.

Every pattern starts from a real engineering problem at Kestrel Transit, a fictional city mobility platform, then generalizes to the kind of question you will see in an interview.

WHAT'S INSIDE
➔ 466 pages · 28 chapters in 6 parts + 4 appendices
➔ 75 patterns, each with "Recognize It" signals, intuition, complexity analysis, and a hand trace
➔ Every pattern solved in Python, Java, and JavaScript
➔ Arrays, hashing, two pointers, sliding window, binary search, intervals, stacks, heaps
➔ Trees, tries, graphs, topological sort, union-find, Dijkstra, MST
➔ Backtracking, dynamic programming, greedy, bit manipulation, math, segment and Fenwick trees
➔ 5 full mock interview walkthroughs and a 4-week / 8-week study plan
➔ Pattern cheat sheet, code templates, and an interview-day checklist

Table Of Contents

PART I — INTERVIEW FOUNDATIONS

• Ch 1 · How Coding Interviews Work — and How to Use This Book
• Ch 2 · Complexity Analysis: Big-O, Space, and Choosing Data Structures
• Ch 3 · A Repeatable Problem-Solving Framework
• Ch 4 · Language Toolkits: Python, Java, and JavaScript for Interviews

PART II — ARRAYS, STRINGS, AND HASHING

• Ch 5 · Hashing Patterns (Patterns 1–4)
• Ch 6 · Two Pointers (Patterns 5–8)
• Ch 7 · Sliding Window (Patterns 9–11)
• Ch 8 · Prefix Sums and Difference Arrays (Patterns 12–14)
• Ch 9 · Binary Search (Patterns 15–17)
• Ch 10 · Intervals, Sorting, and Sweep Line (Patterns 18–20)

PART III — LINEAR DATA STRUCTURES

• Ch 11 · Linked List Patterns (Patterns 21–24)
• Ch 12 · Stacks and Monotonic Stacks (Patterns 25–27)
• Ch 13 · Queues, Deques, and Monotonic Queues (Patterns 28–29)
• Ch 14 · Heaps: Top-K, K-Way Merge, and Two Heaps (Patterns 30–32)

PART IV — TREES AND GRAPHS

• Ch 15 · Tree Traversal Patterns (Patterns 33–36)
• Ch 16 · Binary Search Trees and Tree Construction (Patterns 37–39)
• Ch 17 · Tries and String Search (Patterns 40–41)
• Ch 18 · Graph Traversal: BFS, DFS, and Grids (Patterns 42–45)
• Ch 19 · Topological Sort and Union-Find (Patterns 46–47)
• Ch 20 · Shortest Paths and Minimum Spanning Trees (Patterns 48–50)

PART V — RECURSION, DYNAMIC PROGRAMMING, AND ADVANCED TECHNIQUES

• Ch 21 · Backtracking (Patterns 51–54)
• Ch 22 · Dynamic Programming I: 1D and Knapsack (Patterns 55–58)
• Ch 23 · Dynamic Programming II: Grids, Strings, Intervals, and States (Patterns 59–62)
• Ch 24 · Greedy Algorithms (Patterns 63–65)
• Ch 25 · Bit Manipulation and Math (Patterns 66–69)
• Ch 26 · Advanced Patterns: Design, Range Queries, and String Matching (Patterns 70–75)

PART VI — PUTTING IT ALL TOGETHER

• Ch 27 · Mock Interviews: Five Full Walkthroughs Across the Patterns
• Ch 28 · Your Study Plan: The 75-Pattern Map, Practice Schedules, and Interview Day

APPENDICES

• App A · Pattern Cheat Sheet
• App B · Language Reference and Code Templates
• App C · Interview Day Checklist
• App D · Glossary

WHO IT IS FOR
Job seekers preparing for software engineering interviews, self-taught and bootcamp developers, experienced engineers returning to the job market, and students who want a practical algorithms companion.

FORMAT
PDF (A4), 466 pages, English, clickable table of contents and PDF bookmarks. 1st Edition, 2026. Published by thenexbooks. All problem statements are original.

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