Fill gap interview quiz in ruby.

fill_gap.rb

#!/usr/bin/env ruby
#
#
#              - Water Filling Problem -
# 
#  Imagine we have several columns of bricks forming a
#  wall-like structure just like this,:
# 
#     +-+     +-+       +-+       +-+
#     +-+ +-+-+-+ +-+ +-+-+     +-+-+
#     +-+ +-+-+-+ +-+-+-+-+   +-+-+-+
#     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
#     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
#   ----------------------------------- Ground
#                 fig. 1
# 
#  into which we can pour water.
# 
#  Now given an array of how high each column is, could
#  you calculate how many water we can pour into gaps of
#  this structure?
# 
#  For example, the structure above could be represented
#  with such an array:
#     [4,1,3,3,4,1,3,2,3,4,1,1,2,3,4]
# 
#  and of course here the answer would be 21.  
# 
#  You should implement the fill_gap() function, which
#  takes in an array representing bricks, and gives out
#  how many water we can pour in it.
# 
#  This quest comes with a simple test suite, so that you
#  can easily check your answer just by execting this file.
#
#

def fill_gap(bricks)
  -1
end


# WARN: Don't touch things below me.
def expect(reality, expectation)
  if (reality != expectation)
    puts ("[FAIL] expect #{expectation} while got #{reality}")
  else 
    puts ("[PASS]")
  end
end


expect(
  fill_gap([1,3]),
  0);

expect(
  fill_gap([1, 0, 1]),
  1);

expect(
  fill_gap([3, 0, 2]),
  2);

expect(
  fill_gap([4,1,3,3,4,1,3,2,3,4,1,1,2,3,4]),
  21);

expect(
  fill_gap([4,5,2,3,3,2,3,3,1,5,3,3,3,4]),
  22);