bunch22.rb

#!/usr/bin/ruby1.8
 
def f(x, y)
	
	lo = [lambda { |n| n * 3 + 1 }, lambda { |n| (n * 3 + 1) / 2 }, 
		lambda { |n| n = (n * 3 + 1) / 2 while (n.odd?); n }]
	le = [lambda { |n| n / 2 }, lambda { |n| n /= 2 while (n.even?); n }]

	return lambda \
	{
		|n| 
		n = lo[x].call(n) if (n.odd?)
		n = le[y].call(n) if (n.even?)
		n
	}
	
end


def test()
	
	n = n1 = rand(2 ** 50) | 1

	l = []
	150.times { n2 = $f.call(n); l <<  [n, n2, n2 - n]; n += 2 }

	loop \
	{

		break if ((c = l.select { |x| x[0] < n1 }.size)	== l.size)
		p(c)
		
		l2 = (0...l.size).sort_by { |x| l[x][2] }
		l1 = [l2[-1]]
		d = l[l1[0]][2]

		if (d > 0) then
			
			j = 0
			while (l[l2[j]][2] < 0 && d > 0)
				d += l[l2[j]][2]
				l1 << l2[j]
				j += 1
			end
			return if (d > 0)
		end
	
		d2 = 0
		l1.sort.reverse.each \
		{
			|j|
			x, n, z = l.delete_at(j)
			d2 += z
			n2 = $f.call(n)
			l << [n, n2, n2 - n] if (n != 1)
		}
		
	}


	return n1

end

$f = f(-1, -1)

n = nil
c = 0
loop \
{
	n = test()
	break if (!n.nil?)
	c += 1
}

p([n, c])