platzhirsch's problem

gistfile1.rb

require 'pp'

# Function that solves an interview question commonly known as
# platzhirsch's problem.
def overlap(array, interval)
  left  = array.select { |array_interval| array_interval[1] < interval[0] }
  right = array.select { |array_interval| array_interval[0] > interval[1] }

  rest  = array-left-right

  left + [[rest.first[0] <= interval[0] ? rest.first[0] : interval[0], rest.last[1]  >= interval[1] ? rest.last[1]  : interval[1]]] + right
end

pp overlap(array = [[1, 4], [6, 10], [14, 19]], interval = [13, 17]) # => [1, 4], [6, 10], [13, 19]
pp overlap(array = [[1, 5], [6, 15], [20, 21], [23, 26], [27, 30], [35, 40]], s_interval = [14, 33]) # => [1, 5], [6, 33], [35, 40]