5 ms·

You can replace (\x -> (length x, head x)) with (length &&& head) if you import Control.Arrow to make it fully point free

• eru 16y ago
  And stream fusion should get rid of intermediate data structures.
• jamwt 16y ago
  Good idea re: Arrows, and we can go all out as long as we're using them. :-) rle = group >>> map (length &&& head)