ruby-changes:25447
From: marcandre <ko1@a...>
Date: Wed, 7 Nov 2012 02:11:59 +0900 (JST)
Subject: [ruby-changes:25447] marcandRe: r37504 (trunk): * array.c (rb_ary_repeated_combination): Support for repeated_combination.size
marcandre 2012-11-07 02:11:51 +0900 (Wed, 07 Nov 2012) New Revision: 37504 http://svn.ruby-lang.org/cgi-bin/viewvc.cgi?view=rev&revision=37504 Log: * array.c (rb_ary_repeated_combination): Support for repeated_combination.size [Feature #6636] Modified files: trunk/array.c trunk/test/ruby/test_enumerator.rb Index: array.c =================================================================== --- array.c (revision 37503) +++ array.c (revision 37504) @@ -4645,6 +4645,17 @@ } } +static VALUE +rb_ary_repeated_combination_size(VALUE ary, VALUE args) +{ + long n = RARRAY_LEN(ary); + long k = NUM2LONG(RARRAY_PTR(args)[0]); + if (k == 0) { + return LONG2FIX(1); + } + return binomial_coefficient(k, n + k - 1); +} + /* * call-seq: * ary.repeated_combination(n) { |c| block } -> ary @@ -4678,7 +4689,7 @@ long n, i, len; n = NUM2LONG(num); /* Combination size from argument */ - RETURN_ENUMERATOR(ary, 1, &num); /* Return Enumerator if no block */ + RETURN_SIZED_ENUMERATOR(ary, 1, &num, rb_ary_repeated_combination_size); /* Return enumerator if no block */ len = RARRAY_LEN(ary); if (n < 0) { /* yield nothing */ Index: test/ruby/test_enumerator.rb =================================================================== --- test/ruby/test_enumerator.rb (revision 37503) +++ test/ruby/test_enumerator.rb (revision 37504) @@ -450,6 +450,11 @@ check_consistency_for_combinatorics(:repeated_permutation) assert_equal 291733167875766667063796853374976, (1..42).to_a.repeated_permutation(20).size # 42 ** 20 + + check_consistency_for_combinatorics(:repeated_combination) + assert_equal 28258808871162574166368460400, + (1..59).to_a.repeated_combination(42).size + # 1.upto(100).inject(:*) / 1.upto(42).inject(:*) / 1.upto(58).inject(:*) end end -- ML: ruby-changes@q... Info: http://www.atdot.net/~ko1/quickml/