hasufell/cga
1
1
Fork 0
Code Issues Pull Requests Releases Wiki Activity

Improve redability, add docs

Browse Source
This commit is contained in:
hasufell
2014-10-13 03:25:22 +02:00
parent 87393af71a
commit 2c1d5fa5ec
2 changed files with 17 additions and 12 deletions
Download Patch File Download Diff File Expand all files Collapse all files

17
Algorithms/ConvexHull/GrahamScan.hs
View File

@@ -122,21 +122,28 @@ grahamGetCHSteps c xs' ys'
scanH _ xs _ = xs
-- |Get all iterations of the upper hull of the graham scan algorithm.
grahamGetUpperHullSteps :: [PT] -> [[PT]]
grahamGetUpperHullSteps vs =
(++) [getLastX 2 sortedXY] . rmdups . init . reverse . grahamGetCHSteps ((* 2) . length $ vs) uH $
(++) [getLastX 2 sortedXY] .
rmdups .
init .
reverse .
grahamGetCHSteps ((* 2) . length $ vs) uH $
uHRest
where
sortedXY = fmap p2 . sortLex . fmap unp2 $ vs
(uH, uHRest) = first reverse . splitAt 3 . reverse $ sortedXY
-- |Get all iterations of the lower hull of the graham scan algorithm.
grahamGetLowerHullSteps :: [PT] -> [[PT]]
grahamGetLowerHullSteps vs =
(++) [take 2 sortedXY] . rmdups . reverse . grahamGetCHSteps ((* 2) . length $ vs) lH $ lHRest
(++) [take 2 sortedXY] .
rmdups .
reverse .
grahamGetCHSteps ((* 2) . length $ vs) lH $
lHRest
where
sortedXY = fmap p2 . sortLex . fmap unp2 $ vs
(lH, lHRest) = first reverse . splitAt 3 $ sortedXY
{- - (++) (rmdups . reverse . g ((* 2) . length $ vs) lH $ lHRest) -}
{- - (rmdups . init . reverse . g ((* 2) . length $ vs) uH $ uHRest) -}