プログラマ脳を鍛える数学パズル：Q18

puzzle18.rb

# -- 処理時間計測の自作ライブラリ --
require './process_measure.rb'
# ------------------------------

ROOT_NUM = [4, 9, 16, 25, 36, 49, 64]

def ichigo
  @result = []
  (2..(ROOT_NUM[-1] / 2)).each { |i| search_pair(1, (2..i).to_a, [1]) }
  p @result
end

def search_pair(num, array, build)
  @result = build if (array.size == 0) && ROOT_NUM.include?(num + 1)
  array.each { |opt| search_pair(opt, array - [opt], build + [opt]) if ROOT_NUM.include?(num + opt) }
  false
end

measure_do { ichigo }