add mergesort

- add point sorter
- fix typo in BranchAndMerge
This commit is contained in:
Raffaele Mignone 2019-03-27 17:56:58 +01:00
parent 8c3596d811
commit 46daa16e3c
Signed by: norangebit
GPG Key ID: F5255658CB220573
6 changed files with 300 additions and 6 deletions

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@ -37,10 +37,10 @@ class BranchAndMerge<T>(
companion object {
private const val TMP_FILE_PATH_1 = "/tmp/file1"
private const val TMP_FILE_PATH_2 = "/tmp/file2"
private val GSON = Gson()
}
private val GSON = Gson()
fun run(source: File) {
fun sort(source: File) {
tryBranch(source)
while (!isSorted()) {

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@ -0,0 +1,84 @@
/*
* MIT License
*
* Copyright (c) 2019 norangebit
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*
*/
package it.norangeb.algorithms.exercises
import it.norangeb.algorithms.sorting.Mergesort
data class Point(val x: Double, val y: Double) {
constructor(x: Int, y: Int) : this(x.toDouble(), y.toDouble())
operator fun minus(other: Point): Point {
val x = this.x - other.x
val y = this.y - other.y
return Point(x, y)
}
fun theta(): Double = Math.atan2(y, x)
companion object {
fun thetaComparator(
p1: Point,
p2: Point,
origin: Point = Point(0, 0)
): Int {
var theta1 = (p1 - origin).theta()
var theta2 = (p2 - origin).theta()
if (theta1 < 0) theta1 += 2 * Math.PI
if (theta2 < 0) theta2 += 2 * Math.PI
return theta1.compareTo(theta2)
}
}
}
typealias P = Point
fun main(args: Array<String>) {
if (args.size < 4 || args.size % 2 != 0) return
val origin = P(args[0].toDouble(), args[1].toDouble())
val list = ArrayList<Point>()
for (i in 2 until args.size step 2)
list.add(P(args[i].toDouble(), args[i + 1].toDouble()))
val points = list.toTypedArray()
val compare = { p1: Point, p2: Point ->
Point.thetaComparator(p1, p2, origin)
}
Mergesort.sortWith(points, compare)
println("origin in $origin")
points.forEach {
println(it)
}
}

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@ -0,0 +1,88 @@
/*
* MIT License
*
* Copyright (c) 2019 norangebit
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*
*/
package it.norangeb.algorithms.sorting
object Mergesort : Sorter {
override fun <T : Comparable<T>> sort(array: Array<T>) {
sort(array) { t1, t2 -> t1 < t2 }
}
override fun <T, C : Comparable<C>> sortBy(array: Array<T>, compareBy: (T) -> C) {
sort(array) { t1, t2 -> compareBy(t1) < compareBy(t2) }
}
override fun <T> sortWith(array: Array<T>, compare: (T, T) -> Int) {
sort(array) { t1, t2 -> compare(t1, t2) < 0 }
}
private fun <T> sort(array: Array<T>, isLess: (T, T) -> Boolean) {
val auxiliary = arrayOfNulls<Any>(array.size) as Array<T>
sort(array, auxiliary, 0, array.size - 1, isLess)
}
private fun <T> sort(
array: Array<T>,
auxiliary: Array<T>,
low: Int,
high: Int,
isLess: (T, T) -> Boolean
) {
if (high <= low) return
val mid = low + (high - low) / 2
sort(array, auxiliary, low, mid, isLess)
sort(array, auxiliary, mid + 1, high, isLess)
if (!isLess(array[mid+1], array[mid]))
return
merge(array, auxiliary, low, mid, high, isLess)
}
private inline fun <T> merge(
array: Array<T>,
auxiliary: Array<T>,
low: Int,
mid: Int,
high: Int,
isLess: (T, T) -> Boolean
) {
for (i in low..high)
auxiliary[i] = array[i]
var i = low
var j = mid + 1
for (k in low..high)
when {
i > mid -> array[k] = auxiliary[j++]
j > high -> array[k] = auxiliary[i++]
isLess(auxiliary[j], auxiliary[i]) -> array[k] = auxiliary[j++]
else -> array[k] = auxiliary[i++]
}
}
}

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@ -0,0 +1,32 @@
/*
* MIT License
*
* Copyright (c) 2019 norangebit
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*
*/
package it.norangeb.algorithms.sorting
interface Sorter {
fun <T : Comparable<T>> sort(array: Array<T>)
fun <T, C : Comparable<C>> sortBy(array: Array<T>, compareBy: (T) -> C)
fun <T> sortWith(array: Array<T>, compare: (T, T) -> Int)
}

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@ -281,7 +281,7 @@ class BranchAndMergeTest {
ps.close()
BranchAndMerge(Int::class.java, this::defaultComparator)
.run(File(filePath))
.sort(File(filePath))
File(filePath).readLines()
.map { it.toInt() } `should equal` testSet
@ -297,7 +297,7 @@ class BranchAndMergeTest {
ps.close()
BranchAndMerge(Int::class.java, this::defaultComparator)
.run(File(filePath))
.sort(File(filePath))
File(filePath).readLines()
.map { it.toInt() } `should equal` testSet.sorted()
@ -313,7 +313,7 @@ class BranchAndMergeTest {
ps.close()
BranchAndMerge(Int::class.java) { it1, it2 -> it2.compareTo(it1) }
.run(File(filePath))
.sort(File(filePath))
File(filePath).readLines()
.map { it.toInt() } `should equal` testSet.sorted().reversed()
@ -343,7 +343,7 @@ class BranchAndMergeTest {
}
BranchAndMerge(Person::class.java, sortByAge)
.run(File(filePath))
.sort(File(filePath))
File(filePath).readLines()
.map { gson.fromJson(it, Person::class.java) } `should equal`

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@ -0,0 +1,90 @@
/*
* MIT License
*
* Copyright (c) 2019 norangebit
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*
*/
package it.norangeb.algorithms.sorting
import org.amshove.kluent.`should equal`
import org.junit.jupiter.api.Test
import kotlin.reflect.full.memberFunctions
import kotlin.reflect.jvm.isAccessible
class MergesortTest {
@Test
fun testMerge() {
val merge = Mergesort::class.memberFunctions
.find { it.name == "merge" }
.also { it?.isAccessible = true }
val array = arrayOf(3, 7, 9, 12, 1, 4, 6, 10)
val low = 0
val mid = 3
val high = array.size - 1
val auxiliary = arrayOfNulls<Int>(array.size)
merge?.call(
Mergesort,
array,
auxiliary,
low,
mid,
high,
{ int1: Int, int2: Int ->
int1 < int2
}
)
array `should equal` array.sortedArray()
}
@Test
fun testSort() {
val array = arrayOf(5, 2, 3, 1, 4)
Mergesort.sort(array)
array `should equal` array.sortedArray()
}
@Test
fun testSortBy() {
val array = arrayOf(5, 2, 1, 4, 3)
Mergesort.sortBy(array) { it }
array `should equal` array.sortedArray()
}
@Test
fun testSortWith() {
val array = arrayOf(4, 5, 3, 2, 1)
Mergesort.sortWith(array) { t1, t2 ->
t1.compareTo(t2)
}
array `should equal` array.sortedArray()
}
}