roc-lang/roc
1
1
Fork 0
mirror of https://github.com/roc-lang/roc.git synced 2024-09-20 15:27:45 +03:00
Code Issues Packages Projects Releases Wiki Activity

Update examples/quicksort

Browse Source
This commit is contained in:
Richard Feldman 2020-04-29 20:20:21 -04:00
parent 40607c30c5
commit bcff8b4a57
1 changed files with 27 additions and 22 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

49
examples/quicksort/Quicksort.roc
View File

@ -8,11 +8,14 @@ main =
quicksortHelp : List (Num a), Int, Int -> List (Num a)
quicksortHelp = \list, low, high ->
when partition low high list is
Pair partitionIndex partitioned ->
partitioned
|> quicksortHelp low (partitionIndex - 1)
|> quicksortHelp (partitionIndex + 1) high
if low < high then
when partition low high list is
Pair partitionIndex partitioned ->
partitioned
|> quicksortHelp low (partitionIndex - 1)
|> quicksortHelp (partitionIndex + 1) high
else
list
swap : Int, Int, List a -> List a
@ -26,31 +29,33 @@ main =
_ ->
[]
partition : Int, Int, List (Num a) -> [ Pair Int (List (Num a)) ]
partition = \low, high, initialList ->
when List.get initialList high is
Ok pivot ->
go = \i, j, list ->
if j < high then
when List.get list j is
Ok value ->
if value <= pivot then
go (i + 1) (j + 1) (swap (i + 1) j list)
else
go i (j + 1) list
Err _ ->
Pair i list
else
Pair i list
when go (low - 1) low initialList is
when partitionHelp (low - 1) low initialList high pivot is
Pair newI newList ->
Pair (newI + 1) (swap (newI + 1) high newList)
Err _ ->
Pair (low - 1) initialList
quicksort [ 7, 19, 4, 21 ]
partitionHelp : Int, Int, List (Num a), Int, Int -> [ Pair Int (List (Num a)) ]
partitionHelp = \i, j, list, high, pivot ->
if j < high then
when List.get list j is
Ok value ->
if value <= pivot then
partitionHelp (i + 1) (j + 1) (swap (i + 1) j list) high pivot
else
partitionHelp i (j + 1) list high pivot
Err _ ->
Pair i list
else
Pair i list
quicksort [ 7, 4, 21, 19 ]