Convex Hull Test Algorithm
As well as for finite point sets, convex hulls have also been study for simple polygons, Brownian movement, space curves, and epigraphs of functions. related structures include the orthogonal convex hull, convex layers, Delaunay triangulation and Voronoi diagram, and convex skull. The lower convex hull of points in the airplane looks, in the form of a Newton polygon, in a letter from Isaac Newton to Henry Oldenburg in 1676.The term" convex hull" itself looks as early as the work of Garrett Birkhoff (1935), and the corresponding term in German looks earlier, for case in Hans Rademacher's review of Kőnig (1922).By 1938, according to Lloyd Dines, the term" convex hull" had become standard; Dines adds that he finds the term unfortunate, because the colloquial meaning of the word" hull" would suggest that it refers to the surface of a shape, whereas the convex hull includes the interior and not exactly the surface.
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package com.algorithmexamples.geometry.convexhull
import com.algorithmexamples.geometry.Point
import org.junit.Assert
import org.junit.Test
abstract class ConvexHullTest(val strategy: ConvexHullAlgorithm) {
@Test
fun test1() {
val points = arrayOf(
Point(1, 1),
Point(2, 5),
Point(3, 3),
Point(5, 3),
Point(3, 2),
Point(2, 2)
)
val expected = sortedSetOf(
Point(1, 1),
Point(2, 5),
Point(5, 3)
)
val hull = strategy.convexHull(points)
Assert.assertEquals(expected, hull.toSortedSet())
}
@Test
fun test2() {
val points = arrayOf(
Point(3, 2),
Point(2, 5),
Point(4, 5)
)
val expected = points.toSortedSet()
val hull = strategy.convexHull(points)
Assert.assertEquals(expected, hull.toSortedSet())
}
@Test
fun test3() {
val points = arrayOf(
Point(0, 3),
Point(2, 2),
Point(1, 1),
Point(2, 1),
Point(3, 0),
Point(0, 0),
Point(3, 3)
)
val expected = sortedSetOf(
Point(0, 3),
Point(3, 0),
Point(0, 0),
Point(3, 3)
)
val hull = strategy.convexHull(points)
Assert.assertEquals(expected, hull.toSortedSet())
}
@Test
fun test4() {
val expected = arrayOf(
Point(10, 3),
Point(8, 0),
Point(2, 0),
Point(0, 3),
Point(2, 6),
Point(8, 6)
)
val points = expected + arrayOf(
Point(3, 5),
Point(3, 3),
Point(6, 3),
Point(6, 3),
Point(7, 1),
Point(8, 4)
)
val hull = strategy.convexHull(points)
Assert.assertEquals(expected.toSortedSet(), hull.toSortedSet())
}
@Test(expected= IllegalArgumentException::class)
fun exceptionTest0() {
strategy.convexHull(emptyArray())
}
@Test(expected= IllegalArgumentException::class)
fun exceptionTest1() {
strategy.convexHull(arrayOf(Point(0, 0)))
}
@Test(expected= IllegalArgumentException::class)
fun exceptionTest2() {
strategy.convexHull(arrayOf(Point(0, 0), Point(1, 1)))
}
}
