Best shuffle: Difference between revisions

yy=. (\:#&>)@:(<@({~ ?~@#)@I.@=) y

y C.~ (;yy) </.~ (i.#y) |~ #>{./#@> yy

yy is a (a list of) boxes of (lists of) indices where all characters selected by indices in a box are the same, and where the first box is the biggest box (contains the most indices. The phrase <code>({~ ?~@#)</code> shuffles the indices going into each box which makes the (deterministic) rotate which follows produce differing results sometimes (but only when that is possible).