add red & black BST
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@ -25,66 +25,182 @@
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package it.norangeb.algorithms.datastructures.dictionary
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import arrow.core.None
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import arrow.core.Option
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import arrow.core.toOption
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class RedBlackBST<K : Comparable<K>, V> : OrderedDictionary<K, V> {
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override fun get(key: K): Option<V> {
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TODO("not implemented") // To change body of created functions use File | Settings | File Templates.
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private var root: Option<Node<K, V>> = None
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override fun get(key: K): Option<V> = get(root, key).map { it.value }
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private fun get(
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node: Option<Node<K, V>>,
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key: K
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): Option<Node<K, V>> = node.flatMap {
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when {
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key == it.key -> node
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key > it.key -> get(it.right, key)
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else -> get(it.left, key)
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}
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}
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override fun set(key: K, value: V) {
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TODO("not implemented") // To change body of created functions use File | Settings | File Templates.
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root = set(root, key, value)
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}
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private fun set(
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node: Option<Node<K, V>>,
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key: K,
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value: V
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): Option<Node<K, V>> = normalize(
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node.fold(
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{ Node(key, value) },
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{
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when {
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key == it.key -> it.clone(value = value)
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key > it.key -> it.clone(right = set(it.right, key, value))
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else -> it.clone(left = set(it.left, key, value))
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}
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}
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)
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).toOption()
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private fun normalize(node: Node<K, V>): Node<K, V> {
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var resultNode = node
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if (isRightRed(resultNode))
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resultNode = rotateLeft(resultNode)
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if (isTwoRedInRow(resultNode))
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resultNode = rotateRight(resultNode)
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if (isBothRed(resultNode))
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resultNode = colorFlip(resultNode)
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return resultNode
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}
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private fun rotateRight(node: Node<K, V>): Node<K, V> = node
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.left.fold(
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{ node },
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{
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it.clone(
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color = node.color,
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right = node.clone(color = Color.RED, left = it.right).toOption()
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)
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}
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)
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private fun rotateLeft(node: Node<K, V>): Node<K, V> = node
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.right.fold(
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{ node },
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{
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it.clone(
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color = node.color,
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left = node.clone(color = Color.RED, right = it.left).toOption()
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)
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}
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)
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private fun colorFlip(node: Node<K, V>): Node<K, V> = node.clone(
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color = Color.RED,
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left = node.left.map { it.clone(color = Color.BLACK) },
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right = node.right.map { it.clone(color = Color.BLACK) }
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)
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private fun isRightRed(node: Node<K, V>): Boolean = isRed(node.right) &&
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!isRed(node.left)
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private fun isTwoRedInRow(node: Node<K, V>): Boolean = isRed(node.left) &&
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isRed(node.left.flatMap { it.left })
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private fun isBothRed(node: Node<K, V>): Boolean = isRed(node.left) &&
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isRed(node.right)
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private fun isRed(node: Option<Node<K, V>>): Boolean = node
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.fold(
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{ false },
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{ it.isRed() }
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)
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override fun delete(key: K) {
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TODO("not implemented") // To change body of created functions use File | Settings | File Templates.
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TODO("the same as bst")
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}
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override fun contains(key: K): Boolean {
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TODO("not implemented") // To change body of created functions use File | Settings | File Templates.
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TODO("the same as bst")
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}
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override fun isEmpty(): Boolean {
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TODO("not implemented") // To change body of created functions use File | Settings | File Templates.
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TODO("the same as bst")
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}
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override fun size(): Int {
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TODO("not implemented") // To change body of created functions use File | Settings | File Templates.
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TODO("the same as bst")
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}
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override fun max(): Option<K> {
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TODO("not implemented") // To change body of created functions use File | Settings | File Templates.
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TODO("the same as bst")
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}
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override fun min(): Option<K> {
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TODO("not implemented") // To change body of created functions use File | Settings | File Templates.
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TODO("the same as bst")
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}
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override fun floor(key: K): Option<K> {
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TODO("not implemented") // To change body of created functions use File | Settings | File Templates.
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TODO("the same as bst")
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}
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override fun ceiling(key: K): Option<K> {
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TODO("not implemented") // To change body of created functions use File | Settings | File Templates.
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TODO("the same as bst")
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}
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override fun select(pos: Int): Option<K> {
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TODO("not implemented") // To change body of created functions use File | Settings | File Templates.
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TODO("the same as bst")
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}
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override fun rank(key: K): Int {
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TODO("not implemented") // To change body of created functions use File | Settings | File Templates.
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TODO("the same as bst")
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}
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override fun <R> preOrder(transform: (K) -> R) {
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TODO("not implemented") // To change body of created functions use File | Settings | File Templates.
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override fun <R> preOrder(transform: (K) -> R) = preOrder(root, transform)
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private fun <R> preOrder(node: Option<Node<K, V>>, transform: (K) -> R) {
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node.map {
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transform(it.key)
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preOrder(it.left, transform)
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preOrder(it.right, transform)
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}
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}
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override fun <R> inOrder(transform: (K) -> R) {
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TODO("not implemented") // To change body of created functions use File | Settings | File Templates.
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TODO("the same as bst")
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}
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override fun <R> postOrder(transform: (K) -> R) {
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TODO("not implemented") // To change body of created functions use File | Settings | File Templates.
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TODO("the same as bst")
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}
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data class Node<K, V>(
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val key: K,
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val value: V,
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val color: Color = Color.RED,
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val left: Option<Node<K, V>> = None,
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val right: Option<Node<K, V>> = None
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) {
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fun clone(
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key: K = this.key,
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value: V = this.value,
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color: Color = this.color,
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left: Option<Node<K, V>> = this.left,
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right: Option<Node<K, V>> = this.right
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): Node<K, V> = Node(key, value, color, left, right)
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fun isRed() = color == Color.RED
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}
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enum class Color {
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RED, BLACK
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}
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}
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@ -0,0 +1,164 @@
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/*
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* MIT License
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*
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* Copyright (c) 2019 norangebit
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in all
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* copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*
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*/
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package it.norangeb.algorithms.datastructures.dictionary
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import arrow.core.None
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import arrow.core.Some
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import org.amshove.kluent.`should equal`
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import org.spekframework.spek2.Spek
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import org.spekframework.spek2.style.gherkin.Feature
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object RedBlackBSTTest : Spek({
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Feature("red black tree") {
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Scenario("get and set") {
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val tree by memoized { RedBlackBST<Int, Int>() }
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When("add 1, 3, 4, 6, 8 into tree") {
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tree[1] = 1
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tree[3] = 3
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tree[4] = 4
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tree[6] = 6
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tree[8] = 9
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}
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Then("tree of 1 should equal 1") {
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tree[1] `should equal` Some(1)
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}
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Then("tree of 2 should equal None") {
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tree[2] `should equal` None
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}
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Then("tree of 6 should equal 6") {
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tree[6] `should equal` Some(6)
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}
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Then("tree of 8 should equal 9") {
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tree[8] `should equal` Some(9)
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}
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When("edit 8") {
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tree[8] = 8
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}
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Then("tree of 8 should equal 8") {
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tree[8] `should equal` Some(8)
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}
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}
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Scenario("ordered balance") {
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val tree by memoized { RedBlackBST<Int, Int>() }
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Given("a 1, 2, 3, 4, 5, 6, 7 tree") {
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tree[1] = 1
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tree[2] = 2
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tree[3] = 3
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tree[4] = 4
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tree[5] = 5
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tree[6] = 6
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tree[7] = 7
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}
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val result = mutableListOf<Int>()
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When("compute the preOrder traverse") {
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tree.preOrder { result.add(it) }
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}
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Then("result should equal listOf(4, 2, 1, 3, 6, 5, 7") {
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result `should equal` listOf(4, 2, 1, 3, 6, 5, 7)
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}
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}
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Scenario("reverse balance") {
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val tree by memoized { RedBlackBST<Int, Int>() }
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Given("a 7, 6, 5, 4, 3, 2, 1 tree") {
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tree[7] = 7
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tree[6] = 6
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tree[5] = 5
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tree[4] = 4
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tree[3] = 3
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tree[2] = 2
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tree[1] = 1
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}
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val result = mutableListOf<Int>()
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When("compute the preOrder traverse") {
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tree.preOrder { result.add(it) }
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}
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Then("result should equal listOf(4, 2, 1, 3, 6, 5, 7") {
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result `should equal` listOf(4, 2, 1, 3, 6, 5, 7)
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}
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}
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Scenario("mix balance") {
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val tree by memoized { RedBlackBST<Int, Int>() }
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Given("a 1, 2, 3, 4, 5, 6, 7 tree") {
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tree[6] = 6
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tree[2] = 2
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tree[4] = 4
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tree[1] = 1
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tree[3] = 3
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tree[7] = 7
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tree[5] = 5
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}
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val result = mutableListOf<Int>()
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When("compute the preOrder traverse") {
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tree.preOrder { result.add(it) }
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}
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Then("result should equal listOf(4, 2, 1, 3, 6, 5, 7") {
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result `should equal` listOf(4, 2, 1, 3, 6, 5, 7)
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}
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When("add 8, 9, 10, 12, 13, 14, 15") {
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tree[8] = 8
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tree[9] = 9
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tree[10] = 10
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tree[11] = 11
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tree[12] = 12
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tree[13] = 13
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tree[14] = 14
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tree[15] = 15
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}
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When("compute the preOrder traverse") {
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result.clear()
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tree.preOrder { result.add(it) }
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}
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Then("result should equal listOf(8, 4, 2, 1, 3, 6, 5, 7, 12, 10, 9, 11, 14, 13, 15)") {
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result `should equal` listOf(8, 4, 2, 1, 3, 6, 5, 7, 12, 10, 9, 11, 14, 13, 15)
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}
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}
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}
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})
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