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Merge branch 'master' into beta
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@justcoding121
justcoding121 committed Aug 10, 2020
2 parents 5b85975 + 87c9839 commit 9514748
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Showing 2 changed files with 103 additions and 10 deletions.
28 changes: 19 additions & 9 deletions src/Advanced.Algorithms/Geometry/BentleyOttmann.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -13,7 +13,7 @@ public class BentleyOttmann
private readonly PointComparer pointComparer;

private HashSet<Event> verticalHorizontalLines;
private HashSet<Event> normalLines;
private HashSet<Event> otherLines;

private BHeap<Event> eventQueue;
private HashSet<Event> eventQueueLookUp;
Expand Down Expand Up @@ -42,7 +42,7 @@ private void initialize(IEnumerable<Line> lineSegments)
intersectionEvents = new Dictionary<Point, HashSet<Tuple<Event, Event>>>(pointComparer);

verticalHorizontalLines = new HashSet<Event>();
normalLines = new HashSet<Event>();
otherLines = new HashSet<Event>();

rightLeftEventLookUp = lineSegments
.Select(x =>
Expand Down Expand Up @@ -81,6 +81,7 @@ public Dictionary<Point, List<Line>> FindIntersections(IEnumerable<Line> lineSeg
{
case EventType.Start:

//special case
if (verticalHorizontalLines.Count > 0)
{
foreach (var line in verticalHorizontalLines)
Expand All @@ -90,11 +91,12 @@ public Dictionary<Point, List<Line>> FindIntersections(IEnumerable<Line> lineSeg
}
}

//special case
if (currentEvent.Segment.IsVertical || currentEvent.Segment.IsHorizontal)
{
verticalHorizontalLines.Add(currentEvent);

foreach (var line in normalLines)
foreach (var line in otherLines)
{
var intersection = findIntersection(currentEvent, line);
recordIntersection(currentEvent, line, intersection);
Expand All @@ -103,7 +105,7 @@ public Dictionary<Point, List<Line>> FindIntersections(IEnumerable<Line> lineSeg
break;
}

normalLines.Add(currentEvent);
otherLines.Add(currentEvent);

currentlyTrackedLines.Insert(currentEvent);

Expand All @@ -124,13 +126,14 @@ public Dictionary<Point, List<Line>> FindIntersections(IEnumerable<Line> lineSeg

currentEvent = rightLeftEventLookUp[currentEvent];

//special case
if (currentEvent.Segment.IsVertical || currentEvent.Segment.IsHorizontal)
{
verticalHorizontalLines.Remove(currentEvent);
break;
}

normalLines.Remove(currentEvent);
otherLines.Remove(currentEvent);

lower = currentlyTrackedLines.NextLower(currentEvent);
upper = currentlyTrackedLines.NextHigher(currentEvent);
Expand All @@ -147,18 +150,25 @@ public Dictionary<Point, List<Line>> FindIntersections(IEnumerable<Line> lineSeg

var intersectionLines = intersectionEvents[currentEvent as Point];

foreach (var item in intersectionLines)
foreach (var lines in intersectionLines)
{
swapBstNodes(currentlyTrackedLines, item.Item1, item.Item2);
//special case
if (lines.Item1.Segment.IsHorizontal || lines.Item1.Segment.IsVertical
|| lines.Item2.Segment.IsHorizontal || lines.Item2.Segment.IsVertical)
{
continue;
}

swapBstNodes(currentlyTrackedLines, lines.Item1, lines.Item2);

var upperLine = item.Item1;
var upperLine = lines.Item1;
var upperUpper = currentlyTrackedLines.NextHigher(upperLine);

var newUpperIntersection = findIntersection(upperLine, upperUpper);
recordIntersection(upperLine, upperUpper, newUpperIntersection);
enqueueIntersectionEvent(currentEvent, newUpperIntersection);

var lowerLine = item.Item2;
var lowerLine = lines.Item2;
var lowerLower = currentlyTrackedLines.NextLower(lowerLine);

var newLowerIntersection = findIntersection(lowerLine, lowerLower);
Expand Down
85 changes: 84 additions & 1 deletion tests/Advanced.Algorithms.Tests/Geometry/BentleyOttmann_Tests.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -83,6 +83,89 @@ public void BentleyOttmann_Horizontal_Lines_Test()
Assert.AreEqual(expectedIntersections.Count, actualIntersections.Count);
}

[TestMethod]
public void BentleyOttmann_Vertical_Horizontal_Lines_Test()
{
var lines = new List<Line>();

//vertical
lines.Add(new Line(new Point(100, 100), new Point(100, 200)));
lines.Add(new Line(new Point(125, 100), new Point(125, 200)));
lines.Add(new Line(new Point(150, 100), new Point(150, 200)));
lines.Add(new Line(new Point(175, 100), new Point(175, 200)));
lines.Add(new Line(new Point(200, 100), new Point(200, 200)));

//horizontal
lines.Add(new Line(new Point(100, 100), new Point(200, 100)));
lines.Add(new Line(new Point(100, 125), new Point(200, 125)));
lines.Add(new Line(new Point(100, 150), new Point(200, 150)));
lines.Add(new Line(new Point(100, 175), new Point(200, 175)));
lines.Add(new Line(new Point(100, 200), new Point(200, 200)));

var expectedIntersections = getExpectedIntersections(lines);

var bentleyOttmannAlgorithm = new BentleyOttmann();

var actualIntersections = bentleyOttmannAlgorithm.FindIntersections(lines);

Assert.AreEqual(expectedIntersections.Count, actualIntersections.Count);
}

[TestMethod]
public void BentleyOttmann_Vertical_Horizontal_Other_Lines_Test_1()
{
var lines = new List<Line>();

//vertical
lines.Add(new Line(new Point(100, 100), new Point(100, 200)));
lines.Add(new Line(new Point(200, 100), new Point(200, 200)));

//horizontal
lines.Add(new Line(new Point(100, 100), new Point(200, 100)));
lines.Add(new Line(new Point(100, 150), new Point(200, 150)));
lines.Add(new Line(new Point(100, 200), new Point(200, 200)));

//other lines
lines.Add(new Line(new Point(100, 100), new Point(200, 200)));
lines.Add(new Line(new Point(100, 200), new Point(200, 100)));

var expectedIntersections = getExpectedIntersections(lines);

var bentleyOttmannAlgorithm = new BentleyOttmann();

var actualIntersections = bentleyOttmannAlgorithm.FindIntersections(lines);

Assert.AreEqual(expectedIntersections.Count, actualIntersections.Count);
}


[TestMethod]
public void BentleyOttmann_Vertical_Horizontal_Other_Lines_Test_2()
{
var lines = new List<Line>();

//vertical
lines.Add(new Line(new Point(100, 100), new Point(100, 200)));
lines.Add(new Line(new Point(200, 100), new Point(200, 200)));

//horizontal
lines.Add(new Line(new Point(100, 100), new Point(200, 100)));
lines.Add(new Line(new Point(100, 150), new Point(200, 150)));
lines.Add(new Line(new Point(100, 200), new Point(200, 200)));

//other lines
lines.Add(new Line(new Point(110, 100), new Point(210, 200)));
lines.Add(new Line(new Point(90, 200), new Point(250, 100)));

var expectedIntersections = getExpectedIntersections(lines);

var bentleyOttmannAlgorithm = new BentleyOttmann();

var actualIntersections = bentleyOttmannAlgorithm.FindIntersections(lines);

Assert.AreEqual(expectedIntersections.Count, actualIntersections.Count);
}

[TestMethod]
public void BentleyOttmann_Stress_Test()
{
Expand Down Expand Up @@ -178,7 +261,7 @@ private static List<Line> horizontalLines()
{
var lines = new List<Line>();

var s1 = new Line(new Point(200, 100), new Point(600, 100));
var s1 = new Line(new Point(100, 100), new Point(600, 100));
var s2 = new Line(new Point(225, 100), new Point(625, 100));
var s3 = new Line(new Point(250, 100), new Point(475, 100));
var s4 = new Line(new Point(290, 100), new Point(675, 100));
Expand Down

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