114 lines
3.6 KiB
Kotlin
114 lines
3.6 KiB
Kotlin
/*
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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.exam
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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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import it.norangeb.algorithms.datastructures.queue.Queue
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import it.norangeb.algorithms.datastructures.queue.ResizingArrayQueue
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import kotlin.math.abs
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class DistanceToLeafTree<K : Comparable<K>, V> {
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private var root: Option<Node<K, V>> = None
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operator fun set(key: K, value: V) {
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root = set(key, value, root)
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}
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private fun set(
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key: K,
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value: V,
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node: Option<Node<K, V>>
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): Option<Node<K, V>> = 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(key, value, it.right))
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else -> it.clone(left = set(key, value, it.left))
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}
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}).toOption()
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operator fun get(key: K): Option<V> = get(key, root).map { it.value }
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private fun get(
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key: K,
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node: Option<Node<K, V>>
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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(key, it.right)
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else -> get(key, it.left)
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}
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}
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fun distanceToLeaf(key: K): Option<Int> = get(key, root).map {
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if (it.isLeaf())
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0
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else
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distanceToLeaf(it)
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}
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private fun distanceToLeaf(node: Node<K, V>): Int {
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val toExplore: Queue<Pair<Node<K, V>, Int>> = ResizingArrayQueue()
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node.left.map { toExplore.enqueue(Pair(it, 1)) }
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node.right.map { toExplore.enqueue(Pair(it, 1)) }
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while (!toExplore.isEmpty()) {
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toExplore.dequeue().map { elem ->
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if (elem.first.isLeaf())
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return elem.second
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elem.first.left.map {
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toExplore.enqueue(Pair(it, elem.second + 1))
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}
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elem.first.right.map {
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toExplore.enqueue(Pair(it, elem.second + 1))
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}
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}
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}
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return -1
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}
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private data class Node<K, V>(
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val key: K,
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val value: V,
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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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left: Option<Node<K, V>> = this.left,
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right: Option<Node<K, V>> = this.right
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) = Node(key, value, left, right)
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fun isLeaf() = left == None && right == None
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}
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} |