Sleep Sort in Ruby
Overview
Sleep Sort is humorous algorithm allegedly posted anonymously to 4chan. It involves iterating through the array and firing off a new process for each element. In this process a sleep command is given with a time proportional to the value of the element. When these processes complete, they add their value to the sorted array in order of how long they slept.
Concise
def sleep_sort(a)
t = []
s = []
a.each do |i|
t << Thread.new {
sleep(i)
s << i
}
end
t.each do |i|
i.join
end
s
end
u = (0..9).to_a.sort{ rand() - 0.5 }[0..9]
p u
s = sleep_sort(u)
p sVerbose
# Sleep Sort
#
# Input: A sequence of numbers in any order.
# Output: An ordered sequence from smallest number to largest.
#
def sleep_sort(numbers)
threads = []
sorted = []
# Iterate through the array and create a new thread for each value.
# Inside each thread, sleep for the number of seconds represented by
# the value of the element. Then add the number to the sorted array.
numbers.each do |number|
threads << Thread.new {
sleep(number)
sorted << number
}
end
# Calling `join` means the main thread won't finish until every child
# thread has finished. Otherwise the program will finish before our
# threads are done sleeping, and the array won't be sorted.
threads.each do |thread|
thread.join
end
sorted
end
# Generate array of ten random integers.
unsorted = (0..9).to_a.sort{ rand() - 0.5 }[0..9]
puts unsorted.inspect
# Sort.
sorted = sleep_sort(unsorted)
puts sorted.inspectSample Input and Output
$ ruby sleep_sort.rb
[5, 9, 6, 2, 8, 0, 4, 3, 7, 1]
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]