The Work Gym

Courses / Programming

Coding interview patterns

Practice 150 original coding problems in Python, Java, TypeScript or JavaScript.

Start lesson 1 Practice interview Take the assessmentPractice the first unit of every course. No account needed.

40lessons

248checked exercises

7projects, cases and exams

Prepares you for Coding screens and mock interviews by role

Projects, case studies and mock exams

Project · IntermediateDelivery queue toolbox

Build and test related helpers in one retained source file.

6 steps · 120 min Project · AdvancedBuild scheduler

Build and test related helpers in one retained source file.

6 steps · 120 min Project · ExpertStateful service library

Build and test related helpers in one retained source file.

6 steps · 120 min Case study · ExpertRetry chain investigation

Use checked helper results to distinguish repeated values from a cyclic retry route.

6 steps · 90 min

Build an approach before you code, then test it in a working editor. Start with arrays, hashing and two pointers. Continue through graph traversal, priority queues, dynamic programming, backtracking and stateful designs. Each problem has four language references, boundary tests and an explanation of its time and space cost.

Fresh mixed practice follows the pattern lessons. Projects retain your helper functions across steps. Role and difficulty sets openly reuse named bank problems for rehearsal. For a timed screen with a separate bank, choose two problems in 70 minutes or three in 90 minutes from Take the assessment. Your score includes credit for individual test cases. Mock interviews ask you to explain the contract, complexity and tests before and after coding.

Beginner

Arrays and hashing

Replace repeated scans with a set or a map that remembers what you have seen.

1 lesson

1Arrays and hashingReplace a scan inside a scan with a set or a map you fill as you go.5 exercises · 45 minFree

Two pointers

Walk two indexes through sorted or mirrored data so each step rules out part of the search.

1 lesson

2Two pointersReplace a loop inside a loop with two indexes that each move one way.4 exercises · 45 minWith a plan

Sliding windows

Keep a running total or count for a range of the list, and slide the range instead of starting over.

1 lesson

3Sliding windowsUpdate a total or a count as a window slides, instead of adding up each range again.4 exercises · 50 minWith a plan

Intermediate

Stacks

Keep the items still waiting for a match on a stack, and resolve the newest one first.

1 lesson

4Stack patternsPush what is still waiting, and let each new item resolve the top of the stack.4 exercises · 50 minWith a plan

Binary search

Find boundaries in sorted data, and the smallest answer that passes a yes-or-no test.

1 lesson

5Binary searchHalve the search range at every step, on sorted lists and on answers.5 exercises · 55 minWith a plan

Linked lists

Follow and rewire next references without losing nodes, with dummy heads and fast and slow pointers.

1 lesson

6Linked listsReverse, merge, filter and check linked lists by moving references, not values.4 exercises · 50 minWith a plan

Queue project

Build a reusable queue diagnostic file.

1 lesson

ProjectDelivery queue toolboxBuild and test related helpers in one retained source file.With a plan

Advanced

Trees

Solve tree problems by combining answers from both children, by levels, and by passing bounds down.

1 lesson

8TreesWalk binary trees depth first and level by level, and check search tree order with bounds.4 exercises · 50 minWith a plan

Structures and ordered streams

Use tries, priority queues and structural invariants, then solve fresh transfer problems.

7 lessons

9Trie paths and terminal statesBuild prefix indexes with explicit counts, terminals and search state.5 exercises · 65 minWith a plan

10Heap boundaries and repeated choicesMaintain ranked boundaries with bounded heaps and repeated minimum choices.5 exercises · 65 minWith a plan

11Intervals and greedy frontiersChoose safe sorted scans by proving endpoint and frontier rules.5 exercises · 65 minWith a plan

12Tree contributions and search orderSeparate subtree contributions from complete paths and ordered search results.5 exercises · 65 minWith a plan

13Linked-list boundaries and rewiringRewire list groups while preserving heads, suffixes and stable order.5 exercises · 65 minWith a plan

14Monotonic stacks and dequesDiscard dominated candidates once and preserve strict boundary rules.5 exercises · 65 minWith a plan

Practice setStructures mixed practiceSelect structures and invariants for ten fresh coding tasks.With a plan

Graph and search patterns

Traverse networks, schedule dependencies and search reversible states, then apply them to fresh tasks.

7 lessons

16Graph search stateBFS, components, and coloring through original operational problems.5 exercises · 55 minWith a plan

17Dependency frontiersTopological order and path aggregation through original operational problems.5 exercises · 55 minWith a plan

18Dynamic connectivityDisjoint sets and spanning trees through original operational problems.5 exercises · 55 minWith a plan

19Weighted route stateShortest paths and resource layers through original operational problems.5 exercises · 55 minWith a plan

20Reversible searchChoices, pruning, and restoring state through original operational problems.5 exercises · 55 minWith a plan

21Matrix state graphsBoundary search and extended state through original operational problems.5 exercises · 55 minWith a plan

Practice setGraph and search transfer practiceMixed graph reasoning through original operational problems.With a plan

Build scheduler project

Build dependency ordering, timing, cycle and termination analysis.

1 lesson

ProjectBuild schedulerBuild and test related helpers in one retained source file.With a plan

Expert

Algorithm state and designs

Build dynamic programs, string state and persistent data structures, then choose among them on fresh problems.

7 lessons

24One-dimensional dynamic programmingChoose state meanings and transitions for ordered choices, optimum totals, and reachability.5 exercises · 65 minWith a plan

25Two-dimensional dynamic programmingBuild states over grids, string prefixes, and open intervals.5 exercises · 65 minWith a plan

26Bit manipulationUse XOR cancellation, fixed-width positions, and independent binary masks.5 exercises · 65 minWith a plan

27Geometry and matrix coordinatesTranslate coordinate rules into exact integer calculations and matrix traversals.5 exercises · 65 minWith a plan

28Prefix matching and palindrome structureReuse string borders and prefix states for overlapping search and constrained matching.5 exercises · 65 minWith a plan

29Stateful data structure designPreserve invariants across cache accesses, time boundaries, and iterator operations.5 exercises · 65 minWith a plan

Practice setAlgorithm transfer practiceSelect and combine earlier state, bit, coordinate, and string patterns on fresh problems.With a plan

Stateful services and incident

Build stateful service helpers and investigate a retry incident.

2 lessons

ProjectStateful service libraryBuild and test related helpers in one retained source file.With a plan

Case studyRetry chain investigationUse checked helper results to distinguish repeated values from a cyclic retry route.With a plan

Coding by role and difficulty

Rehearse named bank problems before a timed screen.

8 lessons

Practice setNew graduate engineer practiceRehearse a named selection from the course bank for your target role.With a plan

Practice setBackend engineer practiceRehearse a named selection from the course bank for your target role.With a plan

Practice setFrontend engineer practiceRehearse a named selection from the course bank for your target role.With a plan

Practice setData engineer practiceRehearse a named selection from the course bank for your target role.With a plan

Practice setSenior software engineer practiceRehearse a named selection from the course bank for your target role.With a plan

Interview setEasy coding interview setExplain and implement a selection at one difficulty.With a plan

Interview setMedium coding interview setExplain and implement a selection at one difficulty.With a plan

Interview setHard coding interview setExplain and implement a selection at one difficulty.With a plan