13 lines
350 B
OCaml
13 lines
350 B
OCaml
|
fun quickselect (_, _, []) = raise Fail "empty"
|
||
|
|
| quickselect (k, cmp, x :: xs) = let
|
||
|
|
val (ys, zs) = List.partition (fn y => cmp (y, x) = LESS) xs
|
||
|
|
val l = length ys
|
||
|
|
in
|
||
|
|
if k < l then
|
||
|
|
quickselect (k, cmp, ys)
|
||
|
|
else if k > l then
|
||
|
|
quickselect (k-l-1, cmp, zs)
|
||
|
|
else
|
||
|
|
x
|
||
|
|
end
|