adj5.rb

def f(n)

	n = (n * 3 + 1) if (n.odd?)
	n /= 2 while (n.even?)
	return n
end
	
	
def pair(n)
	
	
	return [n, f(n)]
end
	
def sum(l)
	
	t = 0
	l.each { |x| t += x[0] }
	return t
end

def select(l)
	
	case ARGV[0]
		when '0'
			return (0...l.size).min_by { |x| (l[x][1] - l[x][0]).abs }
		when '1' 
			return (0...l.size).max_by { |x| (l[x][1] - l[x][0]).abs }
	end
	
end


n = 3
l = []
	
1000.times { l << pair(n); n += 2 }

t1 = sum(l)

seen = {}
i = 0

begin
	i += 1
	t = sum(l)

	j = select(l)
	
	z = l[j][1]
	if (seen.member?(z))
		l.delete_at(j)
		next
	end
	seen[z] = nil
	l[j] = pair(z)
	puts([t, l.size].join("\t"))
	
end while (!l.empty?)