hacker_rank_ex2.rb

=begin
  I needed a few more minutes to run an optimization on the hacker rank exercise.
  
  Problem: supply an array arr, such that:
    - We sum each element in the array in sequence
    - During the operation, the current total never drops below 1
    - What is the minimum starting value for a given array?
=end

def min_sum(arr)
  idx = 0
  first_item = arr.first.to_i
  current_min = 1 - first_item
  total = first_item

  valid = false
  while ! valid
    # reduce the size of the array to what's left to compute
    current_arr = arr[idx..-1]

    puts "current_arr length: #{current_arr.length}, current index: #{idx}"

    current_arr.each_with_index do |ss, ii|
      nn = ss.to_i
      puts "current total: #{total} current_min: #{current_min}"
      if total + nn >= 1
        total = total + nn
        if ii == arr.length - 1
          # last item of array, success
          valid = true
        end
      else
        new_index = idx + ii
        puts "stopped at index #{new_index}, total: #{total} nn: #{nn}"
        idx = new_index
        break
      end
    end
  end

  return current_min
end