Binary Search: Templates & Boundaries

Binary Search: Templates & Boundaries

Week 6 notes: binary search is way more than 'find in a sorted array.' The boundary template that stopped my off-by-one bugs, plus searching on the answer itself.

Heaps & Priority Queues

Heaps & Priority Queues

Week 5 notes on heaps: the structure that always keeps its most extreme element one pop away, and how that makes top-K and streaming problems easy.

Queue & Stack: LIFO, FIFO & Monotonic Tricks

Queue & Stack: LIFO, FIFO & Monotonic Tricks

Week 4 notes on two structures defined by how they restrict you: stacks (LIFO) and queues (FIFO), plus the monotonic stack that finally made 'next greater' problems easy.

Hash Tables In Depth: Maps, Sets & Collisions

Hash Tables In Depth: Maps, Sets & Collisions

Week 3 notes on hashing: how buckets and collisions actually work, when that lovely O(1) quietly turns into O(n), and the counting and lookup tricks it buys you.

Array & String Manipulation Patterns

Array & String Manipulation Patterns

Week 2 notes: strings are basically immutable arrays of characters, and that one word (immutable) quietly changes how you write fast code.