「第9回オフラインリアルタイムどう書く」のバス代の問題をRubyで解いてみた

yhpg009.rb

def discount_sub(map, type, a)
  if a > map[type]
    a -= map[type]
    map[type] = 0
    a
  else
    map[type] -= a
    0
  end
end
def discount(map)
  a = (map["An"]+map["Aw"]+map["Ap"]) * 2
  a = discount_sub(map, "In", a)
  discount_sub(map, "Iw", a)
end
def half(x)
  (x+1) / 2
end
def fee(map, u)
  u * map["An"] +
    half(u) * (map["Aw"]+map["Cn"]+map["In"]) +
    half(half(u)) * (map["Cw"]+map["Iw"])
end
def calculate(line)
  map = Hash.new(0)
  (unit, members) = line.split("0:")
  members.split(",").each{|x| map[x] += 1}
  discount(map)
  fee(map, unit.to_i)*10
end
while line=gets
  puts calculate(line.chomp!)
end