Most of these problems are taken from exercism.io !
The exercises are ordered roughly in order of difficulty, but it's a bit haphazard.
# Install ruby:
$ sudo apt-get install ruby
# Go inside your project folder and:
$ ruby *test.rb --verbosehttp://www.commitstrip.com/fr/2016/02/22/when-the-functional-tests-are-all-red/
Write a program that greets the user by name, or by saying "Hello, World!" if no name is given.
1, 2, Fizz, 3, Buzz, Fizz
Write a program that can calculate the Hamming difference between two DNA strands.
Write a program that will calculate the date that someone turned or will celebrate their 1 Gs anniversary.
Write a program that, given a DNA strand, returns its RNA complement (per RNA transcription).
Write a program that converts a number to a string, the contents of which depends on the number's prime factors.
Find the difference between the sum of the squares and the square of the sums of the first N natural numbers.
Determine if a sentence is a pangram.
Write a program that uses the Sieve of Eratosthenes to find all the primes from 2 up to a given number.
Write a function to convert from normal numbers to Roman Numerals: e.g.
Write a program that manages robot factory settings.
Write a program that can tell you what the nth prime is.
Write a program that will take a year and report if it is a leap year.
Write a program that calculates the number of grains of wheat on a chessboard given that the number on each square doubles.
Write a program that given a phrase can count the occurrences of each word in that phrase.
Bob is a lackadaisical teenager. In conversation, his responses are very limited.
Write a program that generates the lyrics of the song 'I Know an Old Lady Who Swallowed a Fly'
Implement run-length encoding and decoding.
Write a program that will convert a binary number, represented as a string (e.g. '101010'), to its decimal equivalent using first principles
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.
Write a program that, given a number, can find the sum of all the multiples of particular numbers up to but not including that number.
Write a small archiving program that stores students' names along with the grade that they are in.
Write a program that will take a string of digits and give you all the contiguous substrings of length `n` in that string.
Write a program that cleans up user-entered phone numbers so that they can be sent SMS messages.
Compute the prime factors of a given natural number.
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.
We are going to do the `Transform` step of an Extract-Transform-Load.
Write a program that will convert a trinary number, represented as a string (e.g. '102012'), to its decimal equivalent using first principles.
Write a program which produces the lyrics to that beloved classic, that field-trip favorite: 99 Bottles of Beer on the Wall.
Score a bowling game
Write a program that, given an age in seconds, calculates how old someone is in terms of a given planet's solar years.
Write a program that, given a word and a list of possible anagrams, selects the correct sublist.
Write a program that inserts numbers and searches in a binary tree.
Implement the classic method for composing secret messages called a square code.
Implement a clock that handles times without dates.
Convert a long phrase to its acronym
Write a program that, given a word, computes the scrabble score for that word.
Given a DNA string, compute how many times each nucleotide occurs in the string.
Write a program that will convert a hexadecimal number, represented as a string (e.g. "10af8c"), to its decimal equivalent using first principles (i.e. no, you may not use built-in or external libraries to accomplish the conversion).
Write a program that will take a number from 0 to 999,999,999,999 and spell out that number in English.
Calculate the date of meetups.
Write a program that positions two queens on a chess board and indicates whether or not they are positioned so that they can attack each other.
Write a program that can detect palindrome products in a given range.
Make sure the brackets and braces all match.
Write a program that, given a string representing a matrix of numbers, can return the rows and columns of that matrix.
Write a program that detects saddle points in a matrix.
Write a program that can tell you if a triangle is equilateral, isosceles, or scalene.
Create an implementation of the atbash cipher, an ancient encryption system created in the Middle East.
Write a program that outputs the nursery rhyme 'This is the House that Jack Built'.
Write a program that will take a decimal number, and convert it to the appropriate sequence of events for a secret handshake.
For want of a horseshoe nail, a kingdom was lost, or so the saying goes. Write a program that outputs the full text of this proverbial rhyme.
Write a program that, given a 3 x 4 grid of pipes, underscores, and spaces, can determine which number is represented, or whether it is garbled.
Implement a program that translates from English to Pig Latin
Write a simple linked list implementation that uses Elements and a List
Write a program that can take a number and determine whether or not it is valid per the Luhn formula.
Implement a simple shift cipher like Caesar and a more secure substitution cipher
Write a program that takes a word problem and returns the answer as an integer.
Write a program that, given a person's allergy score, can tell them whether or not they're allergic to a given item, and their full list of allergies.
Pick the best hand(s) from a list of poker hands.
Write a program that, given a diagram, can tell you which plants each child in the kindergarten class is responsible for.
Implement a doubly linked list
There exists exactly one Pythagorean triplet for which a Find the product a * b * c.
Write a robot simulator.
Write a program that outputs the lyrics to 'The Twelve Days of Christmas'
A data structure that uses a single, fixed-size buffer as if it were connected end-to-end.
Write a program that, when given a string of digits, can calculate the largest product for a contiguous substring of digits of length n.
Write a program that implements a binary search algorithm.
Given two buckets of different size, write a program to demonstrate how to measure an exact number of liters.
Write a program that computes Pascal's triangle up to a given number of rows.
Create a custom set type.
Write a program that adds the numbers to a minesweeper board
Write a program that can generate musical scales, given a starting note and a set of intervals.
Write a program that will translate RNA sequences into proteins.
The Greek mathematician Nicomachus devised a classification scheme for natural numbers.