wmwong

module QuickSort
  def sort(array, options = {})
    start_index = options[:start_index] || 0
    end_index = options[:end_index] || array.length - 1
    unless start_index >= end_index
      # Randomly choose a pivot and swap with the end index.
      pivot_index = rand(end_index - start_index + 1) + start_index
      temp = array[end_index]
      array[end_index] = array[pivot_index]
      array[pivot_index] = temp

wmwong

module Heap
  def parent_index(i)
    # +1 because the math works with indices starting from 1.
    # -1 because we need to convert back to 0-index.
    (i + 1) / 2 - 1
  end

  def left_child_index(i)
    # +1 because the math works with indices starting from 1.
    # -1 because we need to convert back to 0-index.

wmwong

class Anagram
  attr_reader :letters

  def initialize(word)
    @word = word
    # letters is a count of each letter in the word.
    @letters = {}
    @word.each_char do |l|
      @letters[l] ||= 0
      @letters[l] += 1

wmwong

require "digest/md5"

class SpellChecker
  # num_bits is how many bits the hash function should produce.
  def initialize(dictionary_name, num_bits)
    @num_bits = num_bits
    @bitmap = []
    load_dictionary(dictionary_name)
  end

wmwong

module DataMunger
  # This method uses the given regex to parse the data in the given filename
  # to determine the minimum spread.
  # The first match of the regex is the data to return.
  # The second and third match is used to find the spread.
  def min_spread(filename, regex)
    result = nil
    min_spread = nil

    # Go through each line and parse the data.

wmwong

# Iterative by number of iterations.
def chop(target, array)
  found = false
  start_index = 0
  end_index = array.size - 1
  check_index = 0

  # Find the max iterations to perform.
  # log2(0) is infinity so we have a special case for it.
  # After log2(), we +1 because we still need to check the last value. floor()