オフラインリアルタイムどう書く第三回の参考問題解答(Ruby)

def solve(q)
  q.split('').inject([]) {|hist, e|
    o,s,b = hist.empty? ? [0,0,0] : hist.last
    case e
    when 's'
      s += 1
      if s == 3
        s = b = 0
        o += 1
      end
    when 'b'
      b += 1
      s = b = 0 if b == 4
    when 'h'
      s = b = 0
    when 'p'
      s = b = 0
      o += 1
    when 'f'
      s += 1 if s < 2
    end
    o = s = b = 0 if o == 3
    hist << [o,s,b]
  }.map(&:join)
end

DATA.readlines.each do |line|
  q,a = line.chop.split(' -> ')
  puts "#{q} -> #{solve(q).join(',')}"
end

__END__
s -> 010
sss -> 010,020,100
bbbb -> 001,002,003,000
ssbbbb -> 010,020,021,022,023,000
hsbhfhbh -> 000,010,011,000,010,000,001,000
psbpfpbp -> 100,110,111,200,210,000,001,100
ppp -> 100,200,000
ffffs -> 010,020,020,020,100
ssspfffs -> 010,020,100,200,210,220,220,000
bbbsfbppp -> 001,002,003,013,023,000,100,200,000
sssbbbbsbhsbppp -> 010,020,100,101,102,103,100,110,111,100,110,111,200,000,100
ssffpffssp -> 010,020,020,020,100,110,120,200,210,000