Sha256: 41df133e2f19fefd93738538d440ffef84974ac3c38755ec11fbac7ae35d3270
Contents?: true
Size: 644 Bytes
Versions: 5
Compression:
Stored size: 644 Bytes
Contents
unless (RUBY_VERSION[0,3] == '1.9')
class Array
# Permutation provids the possible orders of an enumerable.
# Each is indexed by a permutation number. The maximum number of
# arrangements is the factorial of the size of the array.
#
# CREDIT: Shin-ichiro Hara
def permutation(n=size)
if size < n or n < 0
elsif n == 0
yield([])
else
self[1..-1].permutation(n - 1) do |x|
(0...n).each do |i|
yield(x[0...i] + [first] + x[i..-1])
end
end
self[1..-1].permutation(n) do |x|
yield(x)
end
end
end
end
end
Version data entries
5 entries across 5 versions & 2 rubygems