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Read growth curves at a glance instead of memorising a table.

Pointers, windows and in-place tricks, drawn out step by step.

Characters in a row — palindromes, windows, and the hashing that finds a needle fast.

Watch a search space collapse until only the answer is left.

See why the clever sorts beat the obvious ones.

Follow the pointers — and learn every trick they hide.

Two humble rules, LIFO and FIFO, doing surprisingly heavy lifting.

Trade a bit of memory for answers in constant time.

Watch the call stack grow, shrink, and finally make sense.

Try a choice, go deeper, undo it — and prune the branches that cannot win.

Take the best local move and see exactly when that is enough.

Hierarchies, ordered searches, and the paths between nodes.

A tree of prefixes: autocomplete, word search and spell-check in one shape.

Keep the most important thing on top — without sorting the rest.

Two heaps that lean on each other, and one that merges k sorted streams.

Nodes, edges, and the searches that ripple across them.

Rows, columns and neighbours — the grid problems interviews keep drawing.

Merge groups in near-constant time, then ask who belongs together.

Sort by start, sweep once — merges, overlaps and meeting rooms fall out.

Flip, mask and shift — the tricks that turn a loop into one instruction.

Modular arithmetic, primes and fast powers, drawn so the shortcuts make sense.

Solve every subproblem once, then let the table do the work.

Scale, cache, shard — and know what each choice costs you.

Design a URL shortener, a chat app, a feed — the interview round, end to end.

From embeddings to agents — see how modern AI actually works.

Objects, interfaces and patterns that survive the follow-up question.

Threads, locks and races — watch the interleavings that bite.

Queries you can watch run — joins, groups, indexes, transactions.

Tell true stories that carry signal — and skip the traps.

IAM, S3, queues, VPCs and caches — the AWS round, drawn as requests moving through boxes.

Images, Pods, Services and rollouts — the container round, drawn as replicas moving through a cluster.