From de4d08b93822de5424bb616aaf90519192fac073 Mon Sep 17 00:00:00 2001
From: Arthur Bols <arthur.bolsbe@gmail.com>
Date: Wed, 15 May 2019 16:46:55 +0200
Subject: [PATCH] update

---
 TMI-practicum/Circle.cs             | 10 ++++++----
 TMI-practicum/SimpleAlgorithm.cs    |  8 ++++++--
 TMI-practicum/SweepLineAlgorithm.cs | 10 ++++++----
 3 files changed, 18 insertions(+), 10 deletions(-)

diff --git a/TMI-practicum/Circle.cs b/TMI-practicum/Circle.cs
index 415db43..73f3808 100644
--- a/TMI-practicum/Circle.cs
+++ b/TMI-practicum/Circle.cs
@@ -23,7 +23,7 @@ namespace TMI_practicum
 
         public IList<Intersection> FindIntersections(Circle c1)
         {
-            var intersections = new List<Intersection>();
+            IList<Intersection> intersections;
             double d = Distance(c1);
             if (d > R + c1.R || d < Math.Abs(R - c1.R) || d == 0.0 && R - c1.R == 0.0) return null;
             
@@ -35,13 +35,15 @@ namespace TMI_practicum
             double htemp =  Math.Round(R * R - a * a, 15);
             if (htemp == 0)
             {
-                intersections.Add(new Intersection(px, py));
+                intersections = new Intersection[1];
+                intersections[0] = new Intersection(px, py);
             }
             else
             {
+                intersections = new Intersection[2];
                 double h = Math.Round(Math.Sqrt(htemp), 15);
-                intersections.Add(new Intersection(px + h * (c1.Y - Y) / d, py - h * (c1.X - X) / d));
-                intersections.Add(new Intersection(px - h * (c1.Y - Y) / d, py + h * (c1.X - X) / d));
+                intersections[0] = new Intersection(px + h * (c1.Y - Y) / d, py - h * (c1.X - X) / d);
+                intersections[1] = new Intersection(px - h * (c1.Y - Y) / d, py + h * (c1.X - X) / d);
             }
 
             return intersections;
diff --git a/TMI-practicum/SimpleAlgorithm.cs b/TMI-practicum/SimpleAlgorithm.cs
index 18048b6..afebc16 100644
--- a/TMI-practicum/SimpleAlgorithm.cs
+++ b/TMI-practicum/SimpleAlgorithm.cs
@@ -6,7 +6,7 @@ namespace TMI_practicum
     {
         public static IEnumerable<Intersection> Solve(IList<Circle> circles)
         {
-            var intersections = new List<Intersection>();
+            var intersections = new HashSet<Intersection>();
 
             for (int i = 0; i < circles.Count - 1; i++)
             {
@@ -15,7 +15,11 @@ namespace TMI_practicum
                     var c1 = circles[i];
                     var c2 = circles[j];
                     var intersects = c1.FindIntersections(c2);
-                    if (intersects != null) intersections.AddRange(c1.FindIntersections(c2));
+                    if (intersects == null) continue;
+                    foreach (var intersect in intersects)
+                    {
+                        intersections.Add(intersect);
+                    }
                 }
             }
 
diff --git a/TMI-practicum/SweepLineAlgorithm.cs b/TMI-practicum/SweepLineAlgorithm.cs
index b35bcc0..13061ef 100644
--- a/TMI-practicum/SweepLineAlgorithm.cs
+++ b/TMI-practicum/SweepLineAlgorithm.cs
@@ -9,7 +9,7 @@ namespace TMI_practicum
         public static IEnumerable<Intersection> Solve(IList<Circle> circles)
         {
             var events = new PriorityQueue<Event>();
-            var intersections = new List<Intersection>();
+            var intersections = new HashSet<Intersection>();
             var active = new List<Circle>();
             
             foreach (var circle in circles)
@@ -21,7 +21,6 @@ namespace TMI_practicum
             while (events.Count != 0)
             {
                 Event e = events.Dequeue();
-
                 switch (e.Type)
                 {
                     case Event.EventType.Start:
@@ -39,7 +38,7 @@ namespace TMI_practicum
             return intersections;
         }
 
-        private static void CheckIntersections(IEnumerable<Circle> active, Circle circle, List<Intersection> intersections)
+        private static void CheckIntersections(IEnumerable<Circle> active, Circle circle, HashSet<Intersection> intersections)
         {
             foreach (var otherCircle in active)
             {
@@ -48,7 +47,10 @@ namespace TMI_practicum
                 var intersects = circle.FindIntersections(otherCircle);
                 if (intersects == null) continue;
 
-                intersections.AddRange(intersects);
+                foreach (var intersection in intersects)
+                {
+                    intersections.Add(intersection);
+                }
             }
         }