#!/usr/bin/env ruby


def directions_for_values(values)
  directions = []
  values.each_with_index do |value, index|
    next if index.zero?

    distance = (value.to_i - values[index-1].to_i)
    direction = if (distance.abs > 3 )
                  :err
                elsif distance > 0
                  :up
                elsif distance < 0
                  :down
                else
                  :err
                end

    directions << direction
  end

  return 0 if directions.count(:err) > 1
  directions.uniq.count == 1 ? 1 : 0
end


data = File.read("data.txt")

data = data.split("\n")
data = data.map(&:split)

safe_arr = data.map do |row|
  results = [directions_for_values(row)]

  row.each_with_index do |value, index|
    tmp_arr = row.dup
    tmp_arr.delete_at(index)
    results << directions_for_values(tmp_arr)
  end

  results
end.map(&:sum)


p safe_arr.count { |row| row > 0 }