review84.rb

def f1(n)
	n = (n * 3 + 1) / 2 while (n.odd?)
	n /= 2 while (n.even?)
	return n
end

def f2(n)
	return n.odd? ? (n * 3 + 1) / 2 : n / 2

end

def f3(n)
	return n.odd? ? (n * 3 + 1) : n / 2

end

def load()
	fn = 'mixdb.txt'
	s = File.stat(fn)
	a = {'fn' => Dir.pwd + '/' + fn, 'ct' => s.ctime, 'mt' => s.mtime}
	l = (f = File.open(fn)).readlines.map { |x| Kernel.eval(x) }
	f.close

	a['l_in'] = l.size

	b = {}
	l.each { |x| b[x['n']] = x }
	l = b.values

	a['l_uniq'] = l.size
	$stderr.puts(a.inspect)
	return l

end

def seq(n)

	n1 = n
	l = [n]
	l2 = []
	while (n >= n1 && n != 1)
		l2 << n % 2
		n = $f.call(n)
		l << n
	end
	cm = (0...l.size).max_by { |x| l[x] }
	return {'l' => l, 'l2' => l2.join, 'cm' => cm}
end

def sibling(n)
	s = n.to_s(2)
	s[0..1] = '1'
	return s.to_i(2)
end

def out(a)

        f = File.open($fn, 'a')
        f.puts(a.keys.join("\t")) if (f.size == 0)
	f.puts(a.values.join("\t"))
        f.close
end

def review(n)
	x1 = seq(n)
	x2 = seq(sibling(n))

	s1 = x1['l2']
	s2 = x2['l2']
	i = (0...[s1.length, s2.length].min).to_a.index { |x| s1[x, 1] != s2[x, 1] }
	
	a = {'l1' => x1['l'].size, 'l2' => x2['l'].size, 'i' => i, 'cm' => x1['cm'], 'icm' => i.to_f / x1['cm'] - 1.0}
	w = (a['icm'] <=> 0)
	$c[w] = $c.fetch(w, 0) + 1
	out(a)
end

tf = 2

$f = [lambda { |x| f1(x) }, lambda { |x| f2(x) }, lambda { |x| f3(x) }][tf]
File.open($fn = 'out.txt', 'w').close

l = load()

$c = {}
l.each { |x| review(x['n']) }

$stderr.puts($c.merge({'r' => ($c[1].to_f / l.size).round(3)}))