review16.rb

def f1(n)
        n = (n * 3 + 1) / 2 while (n % 2 == 1)
        n /= 2 while (n % 2 == 0)
        return n
end

def f(n, w)

	n1 = n
	c = nil
	l = []
	while (n >= n1 && n != 1)
		l << n
		n = n * 3 + 1 if (n.odd?)
		if (n.even?) then
			n /= 2
			c = l.size if (w == 0)
			w -= 1
		end
	end
	return c, (0...l.size).max_by { |x| l[x] }
end


l = File.open('db.txt').readlines.map { |z| Kernel.eval(z) }

w = [1, 5, 6, 7]

w.each_with_index \
{
	|i, c|
	a = (i - 1) * 100
	b = a + 99
	l2 = l[a..b].select { |x| x['cg'] > 20}.sort_by { |x| x['cg'] }.reverse
	l2.each \
	{
		|x|
		n = x['n']
		ns = n.to_s(2)
		puts([x['cg'], f(n, ns.length)].join("\t"))
	}
	puts
}