Not a solutions dump.
The reasoning that produces them.
Every question is walked from the constraints to the pattern, to brute force, to the optimal solution — then handed back to you as a script for saying it out loud under pressure. Java throughout.
150 of 150questions published
Written one section at a time. New questions appear here as they're finished.
Part 1 · start here
The Cheatsheet
Every structure, pattern and Java mechanic the 150 require — and nothing they don't. Built by analysing all 150 questions first, then extracting the union. Written to be read cold.
Read the cheatsheet →
23topics
Courses
Part 2 · the questions
All 150, by pattern
Eighteen sections, each one a technique rather than a list. Every question worked from the constraints to the optimal solution, with the script for saying it out loud.
Browse the patterns →18sections