[Haskell-cafe] Errata for "Pearls of Functional Algorithm Design" by Richard Bird, 2010, page 25 #Haskell

[KC]

Errata for "Pearls of Functional Algorithm Design" by Richard Bird,
2010, page 25 #Haskell

smallest :: (Ord a) => Int -> (Array Int a, Array Int a) -> a
smallest k (xa,ya) = search k (0,m+1) (0,n+1)
                        where
                        (0,m) = bounds xa
                        (0,n) = bounds ya

                        search k (lx,rx) (ly,ry)
                            | lx == rx  = ya ! (k+ly)
                            | ly == ry  = xa ! (k+lx)
                            | otherwise = case (xa ! mx < ya ! my, k
<= mx-lx+my-ly) of
                                              (True, True)  -> search
k (lx,rx) (ly,my)
                                              (True, False) -> search
(k-(mx-lx)-1) (mx+1,rx) (ly,ry)
                                              (False, True) -> search
k (lx,mx) (ly,ry)
                                              (False, False)-> search
(k-(my-ly)-1) (lx,rx) (my+1,ry)
                                          where
                                              mx = (lx+rx) `div` 2
                                              my = (ly+ry) `div` 2


-- 
--
Regards,
KC