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Exercises

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149 contributors

315 mentors

23,670
students have developed their Haskell skills on Exercism.

Students

23,670

Submissions

367,408

Mentoring Discussions

14,156

The Haskell track needs attention ⚠️

Building

Build

Use your knowledge to build the Haskell track itself

149 contributors

Build Test Runners

Learn More

Create Test Runners that have the single responsibility of taking a solution, running all tests and returning a standardized output.

Next goal: Get Test Runners to Version 2. Haskell is currently utilising a Version 1 Test Runner. Find out more.

Usage statistics

Total Test Runner Runs

300,595

Test Run Pass Rate

27.3% (82112)

Test Run Fail Rate

65.9% (198211)

Test Run Error Rate

6.7% (20272)

Build Analyzers

Learn More

Build an Analyzer for Haskell: Exercism's analyzers automatically assess student's submissions and provide mentor-style commentary.

Next goal: Build an Analyzer. Find out more.

Build Representers

Learn More

Build a Representer: a bit of code that has the single responsibility of taking a solution and returning a normalized representation of it.

Next goal: Build a Representer. Find out more.

Create Practice Exercises

Learn More

Practice Exercises are exercises designed to allow students to solve an arbitrary problem, with the aim of them making use of the concepts they have learned so far.

Next goal: Implement 128 practice exercises. Find out more.

Usage statistics

96 active practice exercises

Started

Attempts

Completions

Mentoring requests

Hello World

15,422

21,766 (avg. 1.4)

13,280 (86.1%)

6 (0.0%)

Leap

12,285

35,987 (avg. 2.9)

9,628 (78.4%)

2,670 (21.7%)

Space Age

7,881

25,000 (avg. 3.2)

6,186 (78.5%)

1,343 (17.0%)

Pangram

5,613

25,260 (avg. 4.5)

4,150 (73.9%)

872 (15.5%)

Bob

5,376

34,145 (avg. 6.4)

4,029 (74.9%)

1,178 (21.9%)

Collatz Conjecture

3,619

17,837 (avg. 4.9)

2,902 (80.2%)

555 (15.3%)

RNA Transcription

4,380

14,312 (avg. 3.3)

3,685 (84.1%)

1,142 (26.1%)

Nucleotide Count

2,982

9,591 (avg. 3.2)

2,158 (72.4%)

585 (19.6%)

Sum of Multiples

2,968

9,536 (avg. 3.2)

2,440 (82.2%)

418 (14.1%)

Grains

2,849

9,128 (avg. 3.2)

2,548 (89.4%)

519 (18.2%)

Acronym

3,191

9,983 (avg. 3.1)

1,708 (53.5%)

163 (5.1%)

Strain

2,485

4,218 (avg. 1.7)

2,181 (87.8%)

198 (8.0%)

Anagram

2,458

7,349 (avg. 3.0)

1,957 (79.6%)

349 (14.2%)

Clock

1,562

4,883 (avg. 3.1)

1,157 (74.1%)

70 (4.5%)

Crypto Square

1,156

4,290 (avg. 3.7)

780 (67.5%)

74 (6.4%)

Luhn

1,176

3,996 (avg. 3.4)

883 (75.1%)

72 (6.1%)

Nth Prime

1,281

4,128 (avg. 3.2)

881 (68.8%)

36 (2.8%)

Minesweeper

835

2,443 (avg. 2.9)

480 (57.5%)

42 (5.0%)

Perfect Numbers

1,900

4,255 (avg. 2.2)

1,427 (75.1%)

70 (3.7%)

Phone Number

1,526

3,647 (avg. 2.4)

1,254 (82.2%)

176 (11.5%)

Secret Handshake

904

1,900 (avg. 2.1)

718 (79.4%)

22 (2.4%)

Pascal's Triangle

813

1,797 (avg. 2.2)

639 (78.6%)

29 (3.6%)

Binary Search Tree

992

3,123 (avg. 3.1)

704 (71.0%)

71 (7.2%)

Queen Attack

713

2,173 (avg. 3.0)

529 (74.2%)

47 (6.6%)

Word Count

1,063

2,816 (avg. 2.6)

857 (80.6%)

315 (29.6%)

Wordy

468

1,404 (avg. 3.0)

273 (58.3%)

29 (6.2%)

Hamming

2,311

5,063 (avg. 2.2)

1,989 (86.1%)

448 (19.4%)

Robot Simulator

988

2,845 (avg. 2.9)

801 (81.1%)

73 (7.4%)

Twelve Days

664

1,360 (avg. 2.0)

492 (74.1%)

12 (1.8%)

Saddle Points

530

1,118 (avg. 2.1)

329 (62.1%)

9 (1.7%)

Food Chain

344

565 (avg. 1.6)

223 (64.8%)

8 (2.3%)

OCR Numbers

394

759 (avg. 1.9)

279 (70.8%)

15 (3.8%)

Change

424

1,213 (avg. 2.9)

182 (42.9%)

12 (2.8%)

Go Counting

270

331 (avg. 1.2)

97 (35.9%)

5 (1.9%)

Resistor Color Duo

618

861 (avg. 1.4)

511 (82.7%)

12 (1.9%)

D&D Character

445

994 (avg. 2.2)

252 (56.6%)

9 (2.0%)

Resistor Color Trio

457

1,092 (avg. 2.4)

327 (71.6%)

9 (2.0%)

Run-Length Encoding

1,080

2,149 (avg. 2.0)

863 (79.9%)

43 (4.0%)

House

394

520 (avg. 1.3)

282 (71.6%)

15 (3.8%)

Proverb

379

782 (avg. 2.1)

247 (65.2%)

2 (0.5%)

Simple Linked List

1,038

2,124 (avg. 2.0)

827 (79.7%)

86 (8.3%)

Custom Set

401

1,222 (avg. 3.0)

237 (59.1%)

12 (3.0%)

Bowling

251

570 (avg. 2.3)

102 (40.6%)

4 (1.6%)

ISBN Verifier

761

1,612 (avg. 2.1)

589 (77.4%)

20 (2.6%)

Protein Translation

559

1,565 (avg. 2.8)

408 (73.0%)

16 (2.9%)

Yacht

604

2,945 (avg. 4.9)

368 (60.9%)

6 (1.0%)

Pythagorean Triplet

535

1,151 (avg. 2.2)

368 (68.8%)

13 (2.4%)

Rotational Cipher

328

472 (avg. 1.4)

250 (76.2%)

10 (3.0%)

Spiral Matrix

258

340 (avg. 1.3)

160 (62.0%)

2 (0.8%)

Alphametics

213

169 (avg. 0.8)

78 (36.6%)

1 (0.5%)

Beer Song

810

1,556 (avg. 1.9)

691 (85.3%)

130 (16.0%)

List Ops

812

1,816 (avg. 2.2)

648 (79.8%)

97 (11.9%)

Matrix

446

739 (avg. 1.7)

318 (71.3%)

31 (7.0%)

Binary Search

406

673 (avg. 1.7)

214 (52.7%)

2 (0.5%)

Parallel Letter Frequency

299

419 (avg. 1.4)

150 (50.2%)

17 (5.7%)

Transpose

253

427 (avg. 1.7)

133 (52.6%)

2 (0.8%)

Poker

225

231 (avg. 1.0)

73 (32.4%)

2 (0.9%)

Lens Person

303

554 (avg. 1.8)

144 (47.5%)

13 (4.3%)

Triangle

839

1,318 (avg. 1.6)

710 (84.6%)

49 (5.8%)

Meetup

519

791 (avg. 1.5)

394 (75.9%)

64 (12.3%)

Sieve

381

740 (avg. 1.9)

282 (74.0%)

10 (2.6%)

Palindrome Products

247

472 (avg. 1.9)

149 (60.3%)

7 (2.8%)

Simple Cipher

293

532 (avg. 1.8)

170 (58.0%)

13 (4.4%)

Connect

182

158 (avg. 0.9)

83 (45.6%)

3 (1.6%)

POV

209

353 (avg. 1.7)

86 (41.1%)

6 (2.9%)

Difference of Squares

1,705

4,169 (avg. 2.4)

1,454 (85.3%)

95 (5.6%)

Raindrops

908

1,562 (avg. 1.7)

774 (85.2%)

79 (8.7%)

Kindergarten Garden

623

937 (avg. 1.5)

456 (73.2%)

23 (3.7%)

All Your Base

496

1,027 (avg. 2.1)

329 (66.3%)

12 (2.4%)

Allergies

504

713 (avg. 1.4)

413 (81.9%)

54 (10.7%)

Series

467

1,097 (avg. 2.3)

321 (68.7%)

15 (3.2%)

Bank Account

352

578 (avg. 1.6)

234 (66.5%)

52 (14.8%)

Rail Fence Cipher

199

218 (avg. 1.1)

116 (58.3%)

4 (2.0%)

Sublist

977

1,637 (avg. 1.7)

888 (90.9%)

219 (22.4%)

SGF Parsing

175

283 (avg. 1.6)

85 (48.6%)

4 (2.3%)

Zipper

238

375 (avg. 1.6)

132 (55.5%)

6 (2.5%)

Armstrong Numbers

1,048

3,291 (avg. 3.1)

745 (71.1%)

20 (1.9%)

ETL

1,004

1,374 (avg. 1.4)

849 (84.6%)

91 (9.1%)

Scrabble Score

705

1,191 (avg. 1.7)

613 (87.0%)

80 (11.3%)

Roman Numerals

559

828 (avg. 1.5)

443 (79.2%)

69 (12.3%)

Atbash Cipher

397

657 (avg. 1.7)

320 (80.6%)

59 (14.9%)

Pig Latin

192

223 (avg. 1.2)

129 (67.2%)

6 (3.1%)

Robot Name

440

725 (avg. 1.6)

305 (69.3%)

106 (24.1%)

Say

198

271 (avg. 1.4)

120 (60.6%)

5 (2.5%)

Dominoes

232

397 (avg. 1.7)

91 (39.2%)

4 (1.7%)

Accumulate

1,887

2,676 (avg. 1.4)

1,771 (93.9%)

340 (18.0%)

Complex Numbers

524

1,352 (avg. 2.6)

371 (70.8%)

3 (0.6%)

Largest Series Product

561

1,145 (avg. 2.0)

414 (73.8%)

30 (5.3%)

Prime Factors

579

816 (avg. 1.4)

454 (78.4%)

40 (6.9%)

Matching Brackets

476

938 (avg. 2.0)

302 (63.4%)

15 (3.2%)

Linked List

363

616 (avg. 1.7)

162 (44.6%)

18 (5.0%)

Zebra Puzzle

199

143 (avg. 0.7)

94 (47.2%)

3 (1.5%)

Forth

270

535 (avg. 2.0)

95 (35.2%)

5 (1.9%)

Diamond

778

1,105 (avg. 1.4)

525 (67.5%)

19 (2.4%)

Grade School

1,483

2,335 (avg. 1.6)

1,087 (73.3%)

156 (10.5%)

Isogram

1,095

1,887 (avg. 1.7)

848 (77.4%)

35 (3.2%)

5 deprecated practice exercises

Started

Attempts

Completions

Mentoring requests

Binary

141

274 (avg. 1.9)

137 (97.2%)

65 (46.1%)

Gigasecond

536

812 (avg. 1.5)

532 (99.3%)

116 (21.6%)

Hexadecimal

152 (avg. 1.8)

83 (96.5%)

33 (38.4%)

Octal

92 (avg. 1.6)

54 (94.7%)

19 (33.3%)

Trinary

82 (avg. 1.5)

51 (94.4%)

15 (27.8%)

32 unimplemented practice exercises

Affine Cipher

Book Store

Bottle Song

Circular Buffer

DOT DSL

Darts

Error Handling

Flatten Array

Grep

Hangman

High Scores

Killer Sudoku Helper

Knapsack

Ledger

Markdown

Micro Blog

PaaS I/O

REST API

Rational Numbers

React

Rectangles

Reverse String

Satellite

Scale Generator

Square Root

State of Tic-Tac-Toe

Tournament

Tree Building

Two Bucket

Two-Fer

Variable Length Quantity

View data

Word Search

View data

1 foregone practice exercise

Resistor Color

View data

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23,670 students have developed their Haskell skills on Exercism.

The Haskell track needs attention ⚠️

Build

Build Test Runners

Usage statistics

Build Analyzers

Build Representers

Create Practice Exercises

Usage statistics

We 💙 our volunteers

23,670
students have developed their Haskell skills on Exercism.