Exercises on the Go Track | Exercism

Gigasecond

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

Bob

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

Acronym

Convert a long phrase to its acronym

regular expressions

Hello World

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

Space Age

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

floating point numbers

if else statements

Two Fer

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

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.

Scrabble Score

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

Isogram

Determine if a word or phrase is an isogram.

Reverse String

Reverse a string

Difference Of Squares

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

Luhn

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

Grains

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

bitwise operations

if else statements

type conversion

Clock

Implement a clock that handles times without dates.

text formatting

Parallel Letter Frequency

Count the frequency of letters in texts using parallel computation.

Tree Building

Refactor a tree building algorithm.

Robot Name

Manage robot factory settings.

Tournament

Tally the results of a small football competition.

text formatting

Twelve Days

Output the lyrics to 'The Twelve Days of Christmas'

pattern recognition

text formatting

Matrix

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

exception handling

type conversion

Sublist

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

control flow loops

Error Handling

Implement various kinds of error handling and resource management

exception handling

Flatten Array

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

Bank Account

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

PaaS I/O

Report network IO statistics

Leap

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

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.

Triangle

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

Secret Handshake

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

bitwise operations

House

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

text formatting

Pascal's Triangle

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

Series

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

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.

ETL

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

Sum Of Multiples

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

Pythagorean Triplet

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

Pangram

Determine if a sentence is a pangram.

Crypto Square

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

text formatting

Food Chain

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

text formatting

Largest Series Product

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

Sieve

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

Palindrome Products

Detect palindrome products in a given range.

Scale Generator

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

pattern matching

Protein Translation

Translate RNA sequences into proteins.

Perfect Numbers

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

Matching Brackets

Make sure the brackets and braces all match.

Anagram

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

Word Count

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

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

Rail Fence Cipher

Implement encoding and decoding for the rail fence cipher.

text formatting

RNA Transcription

Given a DNA strand, return its RNA Complement Transcription.

Roman Numerals

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

Say

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

text formatting

Circular Buffer

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

Diamond

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

text formatting

React

Implement a basic reactive system.

reactive programming

Custom Set

Create a custom set type.

Atbash Cipher

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

Phone Number

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

regular expressions

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.

Pig Latin

Implement a program that translates from English to Pig Latin

Prime Factors

Compute the prime factors of a given natural number.

Armstrong Numbers

Determine if a number is an Armstrong number

Transpose

Take input text and output it transposed.

Nth Prime

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

Diffie Hellman

Diffie-Hellman key exchange.

Beer Song

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

text formatting

OCR Numbers

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

pattern recognition

Wordy

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

type conversion

Nucleotide Count

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

Grade School

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

Saddle Points

Detect saddle points in a matrix.

Meetup

Calculate the date of meetups.

type conversion

Simple Linked List

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

Linked List

Implement a doubly linked list

Binary Search

Implement a binary search algorithm.

Binary Search Tree

Insert and search for numbers in a binary tree.

Kindergarten Garden

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

Simple Cipher

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

POV

Reparent a graph on a selected node

Minesweeper

Add the numbers to a minesweeper board

Robot Simulator

Write a robot simulator.

Word Search

Create a program to solve a word search puzzle.

All Your Base

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

Connect

Compute the result for a game of Hex / Polygon

Ledger

Refactor a ledger printer.

text formatting

Markdown

Refactor a Markdown parser

text formatting

Yacht

Score a single throw of dice in the game Yacht

pattern matching

Poker

Pick the best hand(s) from a list of poker hands.

pattern matching

Variable Length Quantity

Implement variable length quantity encoding and decoding.

bitwise operations

Forth

Implement an evaluator for a very simple subset of Forth

domain specific languages

Change

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

Bowling

Score a bowling game

Run Length Encoding

Implement run-length encoding and decoding.

Collatz Conjecture

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

control flow loops

Spiral Matrix

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

Book Store

To try and encourage more sales of different books from a popular 5 book series, a bookshop has decided to offer discounts of multiple-book purchases.

floating point numbers

Rotational Cipher

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

Proverb

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

ISBN Verifier

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

Zebra Puzzle

Solve the zebra puzzle.

Dominoes

Make a chain of dominoes.

Alphametics

Write a function to solve alphametics puzzles.

Two Bucket

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

Grep

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

Rectangles

Count the rectangles in an ASCII diagram.

control flow conditionals

control flow loops

List Ops

Implement basic list operations

type conversion

functional programming

Darts

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