construct2.rb

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

end

def re(n, t)

	s = (n % 2).to_s
	n1 = n
	l = [n]
	t.times \
	{
		n = f2(n)
		l << n
		s << (n % 2).to_s
		break if (n == 1)
	}
	return l, s, n
end

def adj(x, m, n, s2, p2, p, x3)
	s2.replace(p[0...x] + (x3 % 2).to_s)
	m = (s2[x, 1] == p[x, 1])
	n = p2.reverse.to_i(2)
	p2[x, 1] = m ? '11' : '01'
	return m, n, x3
end

def terras121(p)
	
	p2 = ['01', '11'][p[0, 1].to_i]
	n = 1
	n3 = 0
	m = p2 == '11'
	x3 = (p2.reverse.to_i(2)) >> 1

	(1...p.length).each \
	{
		|x|

		if (!m)
			ns = n.to_s(2)
			ns[0, 1] = ''
			m1 = x3 - 3**n3
			n1 = f2(m1)
		end

		n3 = p[0...x].split('').select { |z| z == '1' }.size
		
		s2 = ''
		m, n, x3 = adj(x, m, n, s2, p2, p, m ? (f2(x3) + 3**n3) : (n1 + 3**n3))
	}

	n = p2.reverse.to_i(2)

	return n
end

def dense(w, d)
	w2 = w - 1
	
	a = (0...w2).to_a
	s = '0' * w2
	(1..(d * w - 1)).map { a.delete_at(rand(a.size)) }.each { |x| s[x, 1] = '1' }
	return ('1' + s)
	
end

def d(s)
        c = s.split('').select { |x| x == '1' }.size
	d = c.to_f / s.length
        return d
        
end

c2 = Math.log(2)
c3 = Math.log(3)

ns = ''

x = 1
m = 0
l1 = []
c = 100
c.times \
{
	l1 << Math.log(x)
	if (m > c2)
		m -= c2
		ns << '0'
		x /= 2.0
	else
		m += c3 - c2
		ns << '1'
		x *= 3.0 / 2
	end
}

d = d(ns)
$stderr.puts(d)
ns2 = dense(c, d)

n = terras121(ns2)

l, = re(n, ns.length - 1)

puts(['y1', 'y2', 'd', 'y2w'].join("\t"))
c.times \
{ 
	|x|
	y1 = l1[x] - l1[0]
	y2 = Math.log(l[x]) - Math.log(l[0])
	puts([y1, y2, y1 - y2, l[x].to_s(2).length].join("\t"))
}