98 lines
3.1 KiB
Kotlin
98 lines
3.1 KiB
Kotlin
/*
|
|
* 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.exam
|
|
|
|
import arrow.core.None
|
|
import arrow.core.Option
|
|
import arrow.core.toOption
|
|
import kotlin.math.abs
|
|
|
|
class Inbalance<K : Comparable<K>, V> {
|
|
|
|
private var root: Option<Node<K, V>> = None
|
|
|
|
operator fun set(key: K, value: V) {
|
|
root = set(key, value, root)
|
|
}
|
|
|
|
private fun set(
|
|
key: K,
|
|
value: V,
|
|
node: Option<Node<K, V>>
|
|
): Option<Node<K, V>> = node.fold(
|
|
{ Node(key, value) },
|
|
{
|
|
when {
|
|
key == it.key -> it.clone(value = value)
|
|
key > it.key -> it.clone(right = set(key, value, it.right))
|
|
else -> it.clone(left = set(key, value, it.left))
|
|
}
|
|
}).toOption()
|
|
|
|
operator fun get(key: K): Option<V> = get(key, root).map { it.value }
|
|
|
|
private fun get(
|
|
key: K,
|
|
node: Option<Node<K, V>>
|
|
): Option<Node<K, V>> = node.flatMap {
|
|
when {
|
|
key == it.key -> node
|
|
key > it.key -> get(key, it.right)
|
|
else -> get(key, it.left)
|
|
}
|
|
}
|
|
|
|
fun inbalance(key: K): Option<Int> = get(key, root)
|
|
.map { computeInbalance(it) }
|
|
|
|
private fun computeInbalance(node: Node<K, V>): Int {
|
|
val leftLeaf = node.left.fold({ 0 }, { leaf(it) })
|
|
val rightLeaf = node.right.fold({ 0 }, { leaf(it) })
|
|
|
|
return abs(leftLeaf - rightLeaf)
|
|
}
|
|
|
|
private fun leaf(node: Node<K, V>): Int = when {
|
|
node.left == None && node.right == None -> 1
|
|
else ->
|
|
node.left.fold({ 0 }, { leaf(it) }) +
|
|
node.right.fold({ 0 }, { leaf(it) })
|
|
}
|
|
|
|
private data class Node<K, V>(
|
|
val key: K,
|
|
val value: V,
|
|
val left: Option<Node<K, V>> = None,
|
|
val right: Option<Node<K, V>> = None
|
|
) {
|
|
fun clone(
|
|
key: K = this.key,
|
|
value: V = this.value,
|
|
left: Option<Node<K, V>> = this.left,
|
|
right: Option<Node<K, V>> = this.right
|
|
) = Node(key, value, left, right)
|
|
}
|
|
} |