Data commit

Task/Executable-library/Ruby/executable-library-1.rb

@@ -0,0 +1,26 @@
+# hailstone.rb
+module Hailstone
+  module_function
+  def hailstone n
+    seq = [n]
+    until n == 1
+      n = (n.even?) ? (n / 2) : (3 * n + 1)
+      seq << n
+    end
+    seq
+  end
+end
+
+if __FILE__ == $0
+  include Hailstone
+
+  # for n = 27, show sequence length and first and last 4 elements
+  hs27 = hailstone 27
+  p [hs27.length, hs27[0..3], hs27[-4..-1]]
+
+  # find the longest sequence among n less than 100,000
+  n, len = (1 ... 100_000) .collect {|n|
+    [n, hailstone(n).length]} .max_by {|n, len| len}
+  puts "#{n} has a hailstone sequence length of #{len}"
+  puts "the largest number in that sequence is #{hailstone(n).max}"
+end

Task/Executable-library/Ruby/executable-library-2.rb

@@ -0,0 +1,11 @@
+# hsfreq.rb
+require 'hailstone'
+
+h = Hash.new(0)
+last = 99_999
+(1..last).each {|n| h[Hailstone.hailstone(n).length] += 1}
+length, count = h.max_by {|length, count| count}
+
+puts "Given the hailstone sequences from 1 to #{last},"
+puts "the most common sequence length is #{length},"
+puts "with #{count} such sequences."