From: Shumpei Akai <redmine@...>
Date: 2010-08-18T16:33:44+09:00
Subject: [ruby-dev:42067] [Bug #3708] Array#permutation 	がおかしな結果を返す

Bug #3708: Array#permutation がおかしな結果を返す
http://redmine.ruby-lang.org/issues/show/3708

起票者: Shumpei Akai
ステータス: Open, 優先度: Normal
ruby -v: ruby 1.9.3dev (2010-08-18 trunk 29024) [x86_64-darwin10.4.0]

Array#permutationの結果に，配列に含まれていないはずの値が入っています

% ./ruby_head -e "p [0,1,2,3,4][1,4].permutation.to_a"
[[0, 1, 2, 3], [0, 1, 3, 2], [0, 2, 1, 3], [0, 2, 3, 1], [0, 3, 1, 2], [0, 3, 2, 1], [1, 0, 2, 3], [1, 0, 3, 2], [1, 2, 0, 3], [1, 2, 3, 0], [1, 3, 0, 2], [1, 3, 2, 0], [2, 0, 1, 3], [2, 0, 3, 1], [2, 1, 0, 3], [2, 1, 3, 0], [2, 3, 0, 1], [2, 3, 1, 0], [3, 0, 1, 2], [3, 0, 2, 1], [3, 1, 0, 2], [3, 1, 2, 0], [3, 2, 0, 1], [3, 2, 1, 0]]


[0,1,2,3,4][1,4] は [1, 2, 3, 4] なので0は含まれないはずです．


% ./ruby_head -e "p [0,1,2,3][1,3].permutation.to_a"
だと正しく動きます


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