Detecting overlapping ranges in Ruby

Question

I have array of ranges :

[[39600..82800], [39600..70200],[70200..80480]]

I need to determine if there is overlapping or not.What is an easy

Answer 1

Consider this:

class Range
  include Comparable

  def <=>(other)
    self.begin <=> other.begin
  end

  def self.overlap?(*ranges)
    edges = ranges.sort.flat_map { |range| [range.begin, range.end] }
    edges != edges.sort.uniq
  end
end

Range.overlap?(2..12, 6..36, 42..96) # => true

Notes:

1. This could take in any number of ranges.
2. Have a look at the gist with some tests to play with the code.
3. The code creates a flat array with the start and end of each range.
4. This array will retain the order if they don't overlap. (Its easier to visualize with some examples than textually explaining why, try it).