Algorithms

A collection of algorithms implemented in JavaScript and/or Ruby.

For Ruby implementations, you can:

• use the algorithms via a command-line interface
• include them in Ruby apps (where written in Ruby)
• export output to JSON (both via the command-line interface and when included in other apps)

Features

Anagram

Implementations: JavaScript

Check if two strings containing only the characters a-z (lower case alphabetical) are anagrams of each other. Strings that are identical are not considered anagrams. E.g. "tool" and "loot" are anagrams, while "tool" and "fool" are not, and neither are "tool and "tool".

Chessboard

Implementations: JavaScript

Build a string representing a chessboard (using "#" and "_" to represent black and white cells). Optionally customise board size and the strings that appear in alternating cells. By default, the string will be returned, but it can instead be printed directly.

Count unique values

Implementations: JavaScript

Count the number of unique values in an array. E.g. [1, 2, 4] would return 3, [1, 2, 2, 2, 1] would return 2 and [1, 2, "2", 3] would return 4.

First unique character

Implementations: Ruby

Find the first unique (non-repeating) character in a string. A-Z will be converted to a-z; all other characters will be ignored. E.g. "b" if the string is "aaabccc", or "r" if the string is "Esperanza Spalding".

Spiral matrix

Implementations: Ruby

Populate a matrix of size n x n with the numbers 1 to n in a clockwise inward spiral fashion. E.g. if n = 3:

1 2 3

8 9 4

7 6 5

Installation

For Ruby implementations, install Ruby (help), then in a terminal:

1. gem install bundler
2. cd Ruby from within the repository
3. bundle

Javascript installation instructions to follow.

Usage

JavaScript

For now, JavaScript implementations are simply provided as exported functions in a dedicated file per algorithm. You can use these files in an app or copy the function to use within another file.

Anagram

• anagram(stringOne, stringTwo)

Replace stringOne and stringTwo with the two strings you'd like to compare.

Chessboard

Return:

• chessboard()
• chessboard(number)
• chessboard(number, {1: stringOne, 2: stringTwo})

Print (log to console):

• printChessboard()
• printChessboard(number)
• printChessboard(number, {1: stringOne, 2: stringTwo})

Replace number with a number to customise the board size, and stringOne and stringTwo to customise the strings that appear in alternating cells.

Count unique values

• countUniqueValues(array)

Replace array with an array of values.

Ruby

Via command-line interface

To use the command-line interface, which includes a menu of all algorithms:

ruby bin/start from within the Ruby directory (bin/start may work depending on your operating system)

Via another Ruby app

• add require 'pathToFile' to the top section of a Ruby file, replacing 'pathToFile' with the full path to the file specified in the relevant section below (you could also use require_relative and provide a relative path)

First unique character

Path: Algorithms/Ruby/lib/first_unique_character.rb

Class methods

• Algorithms::FirstUniqueCharacter.character(string)
• Algorithms::FirstUniqueCharacter.json(string)
• Algorithms::FirstUniqueCharacter.export_json(string, filepath)

Replace string with a string and, where applicable, filepath with the full filepath (including filename) of where you want the exported JSON file to go.

Spiral matrix

Path: Algorithms/Ruby/lib/spiral_matrix.rb

Class methods

• Algorithms::SpiralMatrix.hash(number)
• Algorithms::SpiralMatrix.json(number)
• Algorithms::SpiralMatrix.export_json(number, filepath)

Replace number with a number and, where applicable, filepath with the full filepath (including filename) of where you want the exported JSON file to go.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/yndajas/Algorithms.

Licence

This app is made available open source under the terms of the MIT License.