Exercises on the JavaScript Track | Exercism

Exercism v3 launches on Sept 1st 2021. Learn more! 🚀🚀🚀

Hello World

The classical introductory exercise. Just say "Hello, World!"

optional values

text formatting

Two Fer

Create a sentence of the form "One for X, one for me."

optional values

text formatting

Resistor Color

Convert a resistor band's color to its numeric representation

Resistor Color Duo

Convert color codes, as used on resistors, to a numeric value.

Gigasecond

Given a moment, determine the moment that would be after a gigasecond has passed.

RNA Transcription

Given a DNA strand, return its RNA Complement Transcription.

Space Age

Given an age in seconds, calculate how old someone is in terms of a given planet's solar years.

floating point numbers

Pangram

Determine if a sentence is a pangram.

Bank Account

Simulate a bank account supporting opening/closing, withdraws, and deposits of money. Watch out for concurrent transactions!

Matrix

Given a string representing a matrix of numbers, return the rows and columns of that matrix.

text formatting

Bob

Bob is a lackadaisical teenager. In conversation, his responses are very limited.

pattern recognition

regular expressions

Pascal's Triangle

Compute Pascal's triangle up to a given number of rows.

text formatting

Linked List

Implement a doubly linked list

optional values

data structures

Grade School

Given students' names along with the grade that they are in, create a roster for the school

List Ops

Implement basic list operations

data structures

Robot Name

Manage robot factory settings.

exception handling

regular expressions

Simple Cipher

Implement a simple shift cipher like Caesar and a more secure substitution cipher

text formatting

Wordy

Parse and evaluate simple math word problems returning the answer as an integer.

exception handling

pattern recognition

regular expressions

Secret Handshake

Given a decimal number, convert it to the appropriate sequence of events for a secret handshake.

bitwise operations

Leap

Given a year, report if it is a leap year.

Square Root

Given a natural radicand, return its square root.

bitwise operations

Reverse String

Reverse a string

Collatz Conjecture

Calculate the number of steps to reach 1 using the Collatz conjecture

exception handling

Triangle

Determine if a triangle is equilateral, isosceles, or scalene.

exception handling

Clock

Implement a clock that handles times without dates.

Meetup

Calculate the date of meetups.

exception handling

ETL

We are going to do the `Transform` step of an Extract-Transform-Load.

Hamming

Calculate the Hamming difference between two DNA strands.

Raindrops

Convert a number to a string, the content of which depends on the number's factors.

Nucleotide Count

Given a DNA string, compute how many times each nucleotide occurs in the string.

text formatting

Scrabble Score

Given a word, compute the Scrabble score for that word.

Allergies

Given a person's allergy score, determine whether or not they're allergic to a given item, and their full list of allergies.

bitwise operations

Word Count

Given a phrase, count the occurrences of each word in that phrase.

regular expressions

Difference Of Squares

Find the difference between the square of the sum and the sum of the squares of the first N natural numbers.

Perfect Numbers

Determine if a number is perfect, abundant, or deficient based on Nicomachus' (60 - 120 CE) classification scheme for positive integers.

Complex Numbers

Implement complex numbers.

Luhn

Given a number determine whether or not it is valid per the Luhn formula.

Prime Factors

Compute the prime factors of a given natural number.

Grains

Calculate the number of grains of wheat on a chessboard given that the number on each square doubles.

Pythagorean Triplet

There exists exactly one Pythagorean triplet for which a + b + c = 1000. Find the product a * b * c.

Palindrome Products

Detect palindrome products in a given range.

exception handling

Anagram

Given a word and a list of possible anagrams, select the correct sublist.

Acronym

Convert a long phrase to its acronym

regular expressions

High Scores

Manage a player's High Score list

Isogram

Determine if a word or phrase is an isogram.

Matching Brackets

Make sure the brackets and braces all match.

exception handling

Phone Number

Clean up user-entered phone numbers so that they can be sent SMS messages.

Series

Given a string of digits, output all the contiguous substrings of length `n` in that string.

exception handling

text formatting

Largest Series Product

Given a string of digits, calculate the largest product for a contiguous substring of digits of length n.

exception handling

regular expressions

Transpose

Take input text and output it transposed.

text formatting

Rectangles

Count the rectangles in an ASCII diagram.

Spiral Matrix

Given the size, return a square matrix of numbers in spiral order.

data structures

OCR Numbers

Given a 3 x 4 grid of pipes, underscores, and spaces, determine which number is represented, or whether it is garbled.

exception handling

text formatting

Saddle Points

Detect saddle points in a matrix.

exception handling

optional values

Forth

Implement an evaluator for a very simple subset of Forth

domain specific languages

Food Chain

Generate the lyrics of the song 'I Know an Old Lady Who Swallowed a Fly'

text formatting

House

Output the nursery rhyme 'This is the House that Jack Built'.

ISBN Verifier

Check if a given string is a valid ISBN-10 number.

pattern recognition

regular expressions

Pig Latin

Implement a program that translates from English to Pig Latin

regular expressions

Proverb

For want of a horseshoe nail, a kingdom was lost, or so the saying goes. Output the full text of this proverbial rhyme.

optional values

text formatting

Twelve Days

Output the lyrics to 'The Twelve Days of Christmas'

pattern recognition

regular expressions

Beer Song

Produce the lyrics to that beloved classic, that field-trip favorite: 99 Bottles of Beer on the Wall.

Resistor Color Trio

Convert color codes, as used on resistors, to a human-readable label.

Say

Given a number from 0 to 999,999,999,999, spell out that number in English.

exception handling

text formatting

Diamond

Given a letter, print a diamond starting with 'A' with the supplied letter at the widest point.

exception handling

text formatting

Rational Numbers

Implement rational numbers.

floating point numbers

Sublist

Write a function to determine if a list is a sublist of another list.

Binary Search Tree

Insert and search for numbers in a binary tree.

Custom Set

Create a custom set type.

data structures

Binary Search

Implement a binary search algorithm.

Circular Buffer

A data structure that uses a single, fixed-size buffer as if it were connected end-to-end.

exception handling

data structures

Simple Linked List

Write a simple linked list implementation that uses Elements and a List

data structures

Word Search

Create a program to solve a word search puzzle.

optional values

text formatting

Variable Length Quantity

Implement variable length quantity encoding and decoding.

bitwise operations

Two Bucket

Given two buckets of different size, demonstrate how to measure an exact number of liters.

exception handling

Alphametics

Write a function to solve alphametics puzzles.

Scale Generator

Generate musical scales, given a starting note and a set of intervals.

pattern recognition

Connect

Compute the result for a game of Hex / Polygon

Bowling

Score a bowling game

exception handling

text formatting

Strain

Implement the `keep` and `discard` operation on collections. Given a collection and a predicate on the collection's elements, `keep` returns a new collection containing those elements where the predicate is true, while `discard` returns a new collection containing those elements where the predicate is false.

Accumulate

Implement the `accumulate` operation, which, given a collection and an operation to perform on each element of the collection, returns a new collection containing the result of applying that operation to each element of the input collection.

Flatten Array

Take a nested list and return a single list with all values except nil/null

Nth Prime

Given a number n, determine what the nth prime is.

exception handling

Sieve

Use the Sieve of Eratosthenes to find all the primes from 2 up to a given number.

Rotational Cipher

Create an implementation of the rotational cipher, also sometimes called the Caesar cipher.

text formatting

Diffie Hellman

Diffie-Hellman key exchange.

exception handling

Affine Cipher

Create an implementation of the Affine cipher, an ancient encryption algorithm from the Middle East.

Atbash Cipher

Create an implementation of the atbash cipher, an ancient encryption system created in the Middle East.

regular expressions

text formatting

Crypto Square

Implement the classic method for composing secret messages called a square code.

regular expressions

text formatting

Robot Simulator

Write a robot simulator.

exception handling

Kindergarten Garden

Given a diagram, determine which plants each child in the kindergarten class is responsible for.

text formatting

Sum Of Multiples

Given a number, find the sum of all the multiples of particular numbers up to but not including that number.

Change

Correctly determine change to be given using the least number of coins

Protein Translation

Translate RNA sequences into proteins.

Armstrong Numbers

Determine if a number is an Armstrong number

Run Length Encoding

Implement run-length encoding and decoding.

exception handling

pattern recognition

regular expressions

text formatting

Darts

Write a function that returns the earned points in a single toss of a Darts game

Roman Numerals

Write a function to convert from normal numbers to Roman Numerals.

pattern recognition

All Your Base

Convert a number, represented as a sequence of digits in one base, to any other base.

exception handling

Minesweeper

Add the numbers to a minesweeper board

Queen Attack

Given the position of two queens on a chess board, indicate whether or not they are positioned so that they can attack each other.

exception handling

optional values

text formatting

React

Implement a basic reactive system.

reactive programming

Zipper

Creating a zipper for a binary tree.

D&D Character

Randomly generate Dungeons & Dragons characters

Grep

Search a file for lines matching a regular expression pattern. Return the line number and contents of each matching line.

text formatting

Yacht

Score a single throw of dice in the game Yacht

Dominoes

Make a chain of dominoes.