From c765c63125db63b674139a4e4bf44fce59240fbd Mon Sep 17 00:00:00 2001
From: hasufell <hasufell@hasufell.de>
Date: Fri, 31 Oct 2014 17:49:08 +0100
Subject: [PATCH] POLYINT: run rmdups only once

---
 Algorithms/PolygonIntersection/Core.hs | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/Algorithms/PolygonIntersection/Core.hs b/Algorithms/PolygonIntersection/Core.hs
index 26d2768..0f32d9f 100644
--- a/Algorithms/PolygonIntersection/Core.hs
+++ b/Algorithms/PolygonIntersection/Core.hs
@@ -105,12 +105,12 @@ sortLexPolys _ = []
 -- |Get all points that intersect between both polygons. This is done
 -- in O(n).
 intersectionPoints :: [PolyPT] -> [PT]
-intersectionPoints []  = []
-intersectionPoints xs' =
-  rmdups $
-    (++) (segIntersections . scanLine $ xs')
-         (intersectionPoints (tail xs'))
+intersectionPoints xs' = rmdups . go $ xs'
   where
+    go [] = []
+    go xs = (++) (segIntersections . scanLine $ xs)
+                 (go (tail xs))
+
     -- Get the scan line or in other words the
     -- Segment pairs we are going to check for intersection.
     scanLine :: [PolyPT] -> ([Segment], [Segment])