Data Structures & Algorithms

From arrays to DP. Learn it visually, then prove it with practice.

By the end you can

Pick the right data structure for a problem and defend its cost
State the invariant behind an algorithm and use it to avoid off-by-one bugs
Recognise the classic interview patterns and code them cleanly under time pressure

Before you start

Syllabus

04
Binary Search
35 min · planned
One comparison against a sorted midpoint discards half the candidates.
Fig · rack of sorted gauge blocks with two sliding stops and a drop probeinvariantlower boundsearch on answer
05
Hashing
40 min
A hash function turns a key into a slot number, so lookup is one jump, until collisions pile up.
Fig · gantry tray sorter: hash dial, shuttle on an overhead rail, eight trays where colliding keys stackhash functionchainingopen addressingload factorresizingworst case
06
Stacks, queues & monotonic stacks
40 min · planned
Only one end is reachable, and that restriction is what makes them fast and useful.
Fig · spring-loaded cafeteria plate dispenserstackqueuedequemonotonic stack