Partition function - James Edward Gray II's ruby implementation

gistfile1.rb

# The partition (combinatoric partition theory) function for a given number
def partition(largest, rest = Array.new, &block)
    block.call([largest] + rest)
    (rest.first || 1).upto(largest / 2) do |i|
        partition(largest - i, [i] + rest, &block)
    end
end

# call the partition function with "5" as a test
partition(5) { |nums| p nums if nums[0] != 5 }