Technical interview answer

ranges.rb

if ARGV.empty?
  puts "\nPlease enter any two SEQUENTIAL random numbers separated by one space. i.e 16 21\n"
  a, b = gets.strip.split(" ")
else
  a, b = ARGV[0], ARGV[1]
end

if a.to_i > 0 && b.to_i == 0
  puts "Please give two numbers."
  exit
elsif a.to_i > b.to_i
  puts "Please make sure the two numbers are in sequential order."
  exit
end

puts "\nOriginal Ranges:"
p array_of_ranges = [[1,3],[5,18],[24,28],[29,30],[33,49]]

new_range = [a.to_i,b.to_i]

if array_of_ranges.first.first > new_range.last
  array_of_ranges.insert 0, new_range
elsif array_of_ranges.last.last < new_range.first
  array_of_ranges.push new_range    
else
  array_of_ranges.each do |check|

    current_range = check.first..check.last

    unless new_range.first < check.first && array_of_ranges.index(check) == 0
      if current_range.include? new_range.first
        @insert_range_left = false
        @left = array_of_ranges.index(check)
      elsif new_range.first < check.first && @left.nil?
        @insert_range_left = true
        @left = array_of_ranges.index(check)
      end
    else
      @left = 0
      @insert_range_left = true
    end

    unless @left.nil?
      if current_range.include? new_range.last
        @insert_range_right = false
        @right = array_of_ranges.index(check)
      elsif new_range.last > check.last
        @insert_range_right = true
        @right = array_of_ranges.index(check)
      end
    end
  end  

  unless @left.nil? || @right.nil?
    if @insert_range_left && !@insert_range_right
      new_range = [new_range.first,array_of_ranges[@right].last]
    elsif !@insert_range_left && @insert_range_right
      new_range = [array_of_ranges[@left].first,new_range.last]
    elsif !@insert_range_left && !@insert_range_right
      new_range = [array_of_ranges[@left].first,array_of_ranges[@right].last]
    end
    array_of_ranges.delete_if { |i| (@left..@right).include?( array_of_ranges.index(i) ) }
  end
  
  array_of_ranges.insert @left, new_range
  
  array_of_ranges.each do |i|
    unless i == array_of_ranges.last
      if i.last == array_of_ranges[array_of_ranges.index(i) + 1].first - 1
        i.concat(array_of_ranges[array_of_ranges.index(i) + 1]).sort!
        array_of_ranges.delete_at array_of_ranges.index(i) + 1
      end
    end
    if i.first == array_of_ranges[array_of_ranges.index(i) - 1].last + 1
      i.concat(array_of_ranges[array_of_ranges.index(i) - 1]).sort!
      array_of_ranges.delete_at array_of_ranges.index(i) - 1
    end
    i.replace([i.first,i.last])
  end
    
end

puts "\nResulting Ranges:"
p array_of_ranges
puts ""

The problem was handed to me like this:

1. Given the pairs (1,3), (5,18), (24,28), (29,30), (33,49)
2. Given another pair (16, 21).
   Each pair represents the beginning and ending value in an inclusive and ordered range. Write a program that will collapse or insert the new range appropriately. Ending result of the given numbers would be (1,3), (5,21), (24,30), (33,49)