Reference cards built from real interview questions and production code. Each one fits on one screen, with complexity notes and common gotchas.
Quick reference for Java Collections — ArrayList, LinkedList, HashMap, Tree…
Complete Java Streams cheat sheet — intermediate and terminal operations, c…
Visual diagram of JVM memory areas — Heap, Young/Old generation, Metaspace,…
Illustrated diagram of Java HashMap internals — hashing, bucket array, coll…
Complete reference for Python built-in functions — type conversion, math, s…
Quick reference for Pandas — DataFrame creation, selection, filtering, grou…
Visual reference for all SQL JOIN types — INNER, LEFT, RIGHT, FULL OUTER, C…
Essential Docker commands reference — containers, images, volumes, networks…
Visual reference for microservices architecture — API gateway, services, me…
Complete DSA quick reference — time/space complexities, Java implementation…