The Code NotebookCrack your tech interview, one page at a time
Simple, notebook-style lessons on data structures, algorithms and Java, made by a developer with 7 years of experience at a product company. Watch free, read the notes, practise the right problems.
Java backend developer · teaching what actually gets asked
Latest lessons
Time & Space Complexity (Big-O)
Count steps, not seconds. The Big-O ladder, space complexity, amortized cost and the constraints trick.
Java Toolkit for DSA
ArrayList, HashMap, HashSet, ArrayDeque, PriorityQueue and TreeMap: which one to use and when, plus 4 Java traps.
Recursion
Base case, call stack, recursion trees and memoization, the foundation for trees, backtracking and DP.
Math for Coding Interviews
Digit tricks, GCD, primes, why mod 10⁹+7, fast power, overflow traps and counting tricks, with LeetCode practice.
📓 Notes for every video
Key ideas, Java code, cost tables and a practice list on every lesson page.
✅ Track your progress
Create a free account and tick off lessons from your dashboard.
🎯 Interview-first
Edge cases, follow-up questions and traps interviewers actually use.
Want everything in one place?
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