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.
45 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
Questions by pattern
01
9 questions
Arrays & Hashing
3 Easy6 Medium→
02
5 questions
Two Pointers
1 Easy3 Medium1 Hard→
03
6 questions
Sliding Window
1 Easy3 Medium2 Hard→
04
7 questions
Stack
1 Easy5 Medium1 Hard→
05
7 questions
Binary Search
1 Easy5 Medium1 Hard→
06
11 questions
Linked List
3 Easy6 Medium2 Hard→
07
0 questions
Trees
→