Crystal

1,713 students

44 contributors

1,713
students have developed their Crystal skills on Exercism.

Students

1,713

Submissions

18,660

Mentoring Discussions

868

The Crystal track needs attention ⚠️

Building

Build

Use your knowledge to build the Crystal track itself

44 contributors

Build Test Runners

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

Usage statistics

Total Test Runner Runs

14,456

Test Run Pass Rate

34.7% (5010)

Test Run Fail Rate

25.7% (3718)

Test Run Error Rate

39.6% (5728)

Build Analyzers

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

Next goal: Build an Analyzer. Find out more.

Build Representers

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

Usage statistics

Total Representer Runs

858

Total Representation Comments Made

0

Feedback Given Frequency

0.0%

Create Practice Exercises

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 129 practice exercises. Find out more.

Usage statistics

82 active practice exercises

Started

Attempts

Completions

Mentoring requests

Hello World

1,188

1,465 (avg. 1.2)

1,011 (85.1%)

5 (0.4%)

Acronym

365

1,988 (avg. 5.4)

213 (58.4%)

16 (4.4%)

Anagram

246

1,100 (avg. 4.5)

195 (79.3%)

14 (5.7%)

Armstrong Numbers

153

530 (avg. 3.5)

129 (84.3%)

6 (3.9%)

Atbash Cipher

176

1,206 (avg. 6.9)

132 (75.0%)

9 (5.1%)

Binary

138

554 (avg. 4.0)

110 (79.7%)

9 (6.5%)

Binary Search Tree

112

838 (avg. 7.5)

44 (39.3%)

10 (8.9%)

Bob

312

714 (avg. 2.3)

249 (79.8%)

72 (23.1%)

Bottle Song

19

57 (avg. 3.0)

15 (78.9%)

0 (0.0%)

Clock

41

307 (avg. 7.5)

33 (80.5%)

1 (2.4%)

Collatz Conjecture

78

296 (avg. 3.8)

62 (79.5%)

5 (6.4%)

Difference of Squares

166

344 (avg. 2.1)

153 (92.2%)

37 (22.3%)

ETL

55

116 (avg. 2.1)

42 (76.4%)

2 (3.6%)

Flatten Array

84

147 (avg. 1.8)

66 (78.6%)

5 (6.0%)

Gigasecond

349

583 (avg. 1.7)

314 (90.0%)

89 (25.5%)

Hamming

546

935 (avg. 1.7)

407 (74.5%)

187 (34.2%)

Isogram

68

232 (avg. 3.4)

57 (83.8%)

6 (8.8%)

Largest Series Product

133

375 (avg. 2.8)

110 (82.7%)

32 (24.1%)

Leap

223

337 (avg. 1.5)

207 (92.8%)

43 (19.3%)

Matching Brackets

180

263 (avg. 1.5)

133 (73.9%)

19 (10.6%)

Pangram

183

382 (avg. 2.1)

164 (89.6%)

41 (22.4%)

Pascal's Triangle

58

201 (avg. 3.5)

42 (72.4%)

1 (1.7%)

Raindrops

240

412 (avg. 1.7)

215 (89.6%)

62 (25.8%)

Resistor Color

51

106 (avg. 2.1)

42 (82.4%)

4 (7.8%)

Resistor Color Duo

49

213 (avg. 4.3)

39 (79.6%)

5 (10.2%)

Reverse String

70

118 (avg. 1.7)

59 (84.3%)

3 (4.3%)

Rotational Cipher

13

54 (avg. 4.2)

13 (100.0%)

1 (7.7%)

RNA Transcription

301

569 (avg. 1.9)

277 (92.0%)

72 (23.9%)

Roman Numerals

108

166 (avg. 1.5)

80 (74.1%)

6 (5.6%)

Run-Length Encoding

67

136 (avg. 2.0)

45 (67.2%)

4 (6.0%)

Scrabble Score

48

135 (avg. 2.8)

39 (81.3%)

3 (6.3%)

Sieve

125

173 (avg. 1.4)

94 (75.2%)

10 (8.0%)

Space Age

46

92 (avg. 2.0)

33 (71.7%)

2 (4.3%)

Triangle

160

437 (avg. 2.7)

133 (83.1%)

46 (28.7%)

Two Fer

64

73 (avg. 1.1)

55 (85.9%)

5 (7.8%)

Darts

38

102 (avg. 2.7)

31 (81.6%)

3 (7.9%)

Resistor Color Trio

13

299 (avg. 23.0)

10 (76.9%)

2 (15.4%)

ISBN Verifier

40

188 (avg. 4.7)

29 (72.5%)

0 (0.0%)

Luhn

43

275 (avg. 6.4)

27 (62.8%)

1 (2.3%)

Strain

39

49 (avg. 1.3)

26 (66.7%)

0 (0.0%)

Binary Search

9

50 (avg. 5.6)

8 (88.9%)

0 (0.0%)

Phone Number

10

128 (avg. 12.8)

8 (80.0%)

1 (10.0%)

Nucleotide Count

9

45 (avg. 5.0)

8 (88.9%)

1 (11.1%)

High Scores

11

25 (avg. 2.3)

11 (100.0%)

1 (9.1%)

All Your Base

28

104 (avg. 3.7)

18 (64.3%)

1 (3.6%)

Wordy

8

10 (avg. 1.3)

5 (62.5%)

0 (0.0%)

Saddle Points

2

1 (avg. 0.5)

1 (50.0%)

0 (0.0%)

Forth

60

146 (avg. 2.4)

34 (56.7%)

7 (11.7%)

Meetup

32

70 (avg. 2.2)

20 (62.5%)

1 (3.1%)

Nth Prime

31

186 (avg. 6.0)

21 (67.7%)

2 (6.5%)

Prime Factors

28

59 (avg. 2.1)

20 (71.4%)

0 (0.0%)

Protein Translation

37

81 (avg. 2.2)

29 (78.4%)

3 (8.1%)

Series

34

122 (avg. 3.6)

25 (73.5%)

0 (0.0%)

Sublist

5

9 (avg. 1.8)

5 (100.0%)

0 (0.0%)

Word Count

12

48 (avg. 4.0)

10 (83.3%)

0 (0.0%)

Matrix

4

8 (avg. 2.0)

2 (50.0%)

0 (0.0%)

Queen Attack

2

2 (avg. 1.0)

2 (100.0%)

0 (0.0%)

Robot Simulator

10

43 (avg. 4.3)

10 (100.0%)

0 (0.0%)

Killer Sudoku Helper

3

6 (avg. 2.0)

2 (66.7%)

0 (0.0%)

Minesweeper

2

1 (avg. 0.5)

1 (50.0%)

0 (0.0%)

Bank Account

3

4 (avg. 1.3)

3 (100.0%)

0 (0.0%)

Palindrome Products

6

20 (avg. 3.3)

4 (66.7%)

1 (16.7%)

Linked List

9

116 (avg. 12.9)

6 (66.7%)

0 (0.0%)

Allergies

39

102 (avg. 2.6)

29 (74.4%)

3 (7.7%)

Grains

58

172 (avg. 3.0)

44 (75.9%)

3 (5.2%)

Perfect Numbers

51

74 (avg. 1.5)

38 (74.5%)

1 (2.0%)

Proverb

42

58 (avg. 1.4)

32 (76.2%)

3 (7.1%)

Pig Latin

2

1 (avg. 0.5)

1 (50.0%)

0 (0.0%)

Diamond

4

13 (avg. 3.3)

4 (100.0%)

0 (0.0%)

Rail Fence Cipher

3

6 (avg. 2.0)

2 (66.7%)

0 (0.0%)

Rational Numbers

2

1 (avg. 0.5)

1 (50.0%)

0 (0.0%)

Secret Handshake

42

66 (avg. 1.6)

27 (64.3%)

1 (2.4%)

Sum of Multiples

42

115 (avg. 2.7)

31 (73.8%)

0 (0.0%)

Pythagorean Triplet

7

15 (avg. 2.1)

5 (71.4%)

0 (0.0%)

State of Tic-Tac-Toe

2

1 (avg. 0.5)

1 (50.0%)

0 (0.0%)

Change

4

15 (avg. 3.8)

3 (75.0%)

0 (0.0%)

Dominoes

2

2 (avg. 1.0)

1 (50.0%)

0 (0.0%)

Connect

3

3 (avg. 1.0)

1 (33.3%)

0 (0.0%)

React

109

139 (avg. 1.3)

42 (38.5%)

5 (4.6%)

Say

2

1 (avg. 0.5)

1 (50.0%)

0 (0.0%)

Two Bucket

4

1 (avg. 0.3)

1 (25.0%)

0 (0.0%)

Alphametics

1

0 (avg. 0.0)

0 (0.0%)

0 (0.0%)

47 unimplemented practice exercises

Affine Cipher

Book Store

Bowling

Circular Buffer

Complex Numbers

Crypto Square

Custom Set

D&D Character

DOT DSL

Error Handling

Food Chain

Go Counting

Grade School

Grep

Hangman

House

Kindergarten Garden

Knapsack

Ledger

Lens Person

List Ops

Markdown

Micro Blog

OCR Numbers

POV

PaaS I/O

Parallel Letter Frequency

Poker

REST API

Rectangles

Robot Name

SGF Parsing

Satellite

Scale Generator

Simple Cipher

Simple Linked List

Spiral Matrix

Square Root

Tournament

Transpose

Tree Building

Twelve Days

Variable Length Quantity

Word Search

Yacht

Zebra Puzzle

Zipper

Volunteers

68

tenebrousedge

1,833

Meatball

1,692

amscotti

1,366

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