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def count_inversion arr

  def count_and_merge arr1, arr2
    arr = []
    j = 0
    i = 0
    count = 0
    while (i != arr1.size) && (j != arr2.size)

      if arr1[i] < arr2[j]

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class Numeric
  def find_last_bit
    r = 0
    n = self
    32.times do
      n >>= 1
      break if n==0
      r = r+1
    end
    return r

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def mergesort arr

  def merge arr1, arr2
  
    arr = []
    j = 0
    i = 0
    while (i != arr1.size) && (j != arr2.size)
      if arr1[i] < arr2[j]
        arr << arr1[i]

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def reverse_word str

  str.split(" ").reverse.join(" ")

end

reverse_word "This is really awesome"

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#To get a column from a Model 

Movie.all  # Returns all row from the table Movies

Movie.select(:title).map { |m| m.title } # Returns array of title from the Model movie
Movie.select(:title).map(&:title)  # Returns array of title from the Model movie

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def closestpair points

  px = points

  def euclid_distance pt1, pt2
    Math.sqrt ((pt1[0] - pt2[0])**2 + (pt1[1] - pt2[1])**2)
  end

  def closestsplitpair pts, minpt, dist 

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def quicksort arr,startpos,endpos

  def choose_pivot arr,startpos,endpos

    #THis is for selecting median of three , you can return a random number as well. 

    if ((arr[startpos] < arr[endpos]) and (arr[startpos] > arr[startpos+ (endpos-startpos)/2])) or ((arr[startpos] > arr[endpos]) and (arr[startpos] < arr[startpos+ (endpos-startpos)/2]))      
      return startpos
    elsif ((arr[endpos] < arr[startpos]) and (arr[endpos] > arr[startpos+ (endpos-startpos)/2])) or ((arr[endpos] > arr[startpos]) and (arr[endpos] < arr[startpos+ (endpos-startpos)/2]))
      return endpos

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require 'set'

def twosum arr,sum_arr

  a = Set.new(arr)
  sum_arr.each do |sum|
    count = 0
    arr.each do |elem|
      puts("#{sum} = #{elem} + #{sum-elem}") if a.include? (sum-elem)      
    end

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def second_smallest arr

  min_arr = []

  arr.each_slice(2) do |x,y|
    if y.nil? or x < y 
      min_arr << x
    else
      min_arr << y 
    end

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class Heap

  def initialize arr, type=:min
    @heap = arr
    self.class.class_eval { alias_method "get#{type.to_s}", :getroot } 
    if type == :min
      @op = :<
    else
      @op = :>
    end