The problem catalog: 548 picks

548 selected problems covering the full data-structure and algorithm spectrum.

255 Easy 240 Medium 53 Hard Open the Darbar →
Standard path

One “Standard” solve path to keep the 108-week core viable.

Auror path

Solve, explain, and timebox all 548 catalog slots.

Pacing map

The emphasis shifts with the phase of the course, and each set points to a production concept.

WeeksDarbar emphasisProduction connection
1–6 Arrays, strings, hash tables, stacks, queues, searching/sorting Python engineering, APIs, diagnostics
7–30 Math, bit manipulation, divide and conquer, recursion, backtracking Linear algebra, probability, statistics, optimization
31–45 Heaps, linked lists, tries, range queries, hashing Retrieval, Top-K, caching, sketches, routing
46–57 Graphs, trees, greedy, DSU, range queries System design, workflows, sharding, scheduling
58–69 Dynamic programming, greedy, math, probability Experiment assignment, rollouts, monitoring
70–81 Strings, tries, graphs, sequence DP Tokenization, retrieval, agents, guardrails
82–102 Heaps, priority queues, graphs, trees, range queries Inference schedulers, quotas, queues, tenant fairness
103–108 Mixed timed sets and mock interviews Mo's traces, Euler/DSU boss, portfolio defense
Weekly operating rule
  • Mon–Thu: one catalog problem per day
  • Fri: one timed problem or contest set
  • Weekend: review, editorial rewrite, or recovery
Pattern blocks
PatternWeeksSlotsFocus & tipsTimed exam
Timed routing 1–15 1–120 Two-pointer scanning, map-based lookups, prefix products, interval merging Weekly timed block, 3–5 problems in 60 minutes
State machines & simulations 16–30 121–200 Transition tables, cycle detection in simulation, stack/queue state 2–3 state-machine problems in 60 minutes
Tree & graph fluency 31–45 201–280 DFS/BFS patterns, subtree invariants, shortest-path frames, topo order Tree+graph block with one design flavored problem
Data-structure mastery 46–60 281–360 Heaps, Fenwick/segment trees, tries, DSU, balanced structures Structure-selection exam with 2–3 advanced problems
Advanced & interview fusion 61–90 361–470 DP, greedy, sliding-window optimizations, offline queries Mixed 4-problem block mirroring a real interview
Mock & personal gauntlet 91–108 471–548 Full mock interviews, random pick from all patterns, time pressure Full mock interviews scored on a rubric
Concept triangulation

The Darbar is one leg of three. The same concept is drilled for speed here, derived for depth in the Forge, and placed into a production artifact by the core course.

ConceptDarbar speed setForge depthTensor-to-Tenant artifact
Heap Top-K and scheduler problems Heap invariants and adversarial streams Streaming Top-K / inference batching
Trees Traversal, LCA, tree DP Euler Tour, HLD, DSU on Tree Agent-execution forensics
Graphs BFS/DFS and shortest paths SCC, flow, matching, min-cost flow Workflow and routing platform
Strings Prefix matching and tries KMP, Aho-Corasick, suffix structures PII detector / retrieval index
Hashing Frequency and lookup patterns Consistent/rendezvous hashing Tenant-aware routing and caches
Category spine

The catalog is organized across the full data-structure and algorithm spectrum:

arraybacktrackingbit manipulationdivide and conquerdynamic programminggraphsgreedyhash tableheaplinked listmathqueuerange queryrecursionsearching and sortingstackstringtreestrie
Principles
  • Rigor with sanity: prioritize problems that force the phase’s algorithms.
  • Timer on, then review: solve under a clock, then study the editorial regardless of outcome.
  • Evidence per slot: one file that proves the attempt, the solution, and the complexity note.
  • Patterns before volume: mastery is choosing the right tool for the workload, not memorizing solutions.
  • Mock pressure from week one: the timed block is a permanent part of the ritual.
  • Auror track is optional: the 548-slot catalog is depth; the 108-week path never depends on it.
Why a separate lane?

The Darbar is tracked independently so standard learners can keep the 108-week path viable while Auror learners can solve and explain all 548 catalog slots. It never becomes a hidden prerequisite for the core course.