2178.rb

# 2178. Maximum Split of Positive Even Integers
# Input: finalSum = 12
# Output: [2,4,6]

# Input: finalSum = 7
# Output: []

def maximum_even_split(final_sum)
  # return [] if odd(not even) number
  return [] if final_sum % 2 != 0
  
  # elseif
  integers = []

  i = 0
  digit = 0
  while final_sum > 0 do
    # if remainder of difference is already included don't include that
    i += 2
    
    if !(integers.include? (final_sum - i))
      final_sum -= i
      integers << i
      # p integers
    end

    if !integers.empty? && final_sum == i
      integers << digit unless digit.zero?
      digit = integers.delete_at(0)
      final_sum += digit
    end
  end
  # p "-------------------------------------"
  return integers
end

# p maximum_even_split(6914017674).reduce(:+)
p maximum_even_split(28)
# n = 1
# while n < 10000000000 do
#   array = maximum_even_split(n)
#   unless array.empty?
#     if n != array.reduce(:+)
#       p false
#     end
#   end
#   n += 1
# end