111 lines
3.1 KiB
Kotlin
111 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.datastructures.stack
|
|
|
|
import arrow.core.None
|
|
import arrow.core.Option
|
|
import arrow.core.toOption
|
|
|
|
class ResizingArrayStack<T>(capacity: Int = DEFAULT_CAPACITY) : Stack<T> {
|
|
private var stack: Array<T?> = arrayOfNulls<Any>(capacity) as Array<T?>
|
|
private var size = 0
|
|
|
|
override fun isEmpty(): Boolean = size == 0
|
|
|
|
private fun isFull(): Boolean = size == stack.size
|
|
|
|
override fun size(): Int = size
|
|
|
|
override fun peek(): Option<T> = if (size == 0)
|
|
None
|
|
else
|
|
stack[size - 1].toOption()
|
|
|
|
override fun pop(): Option<T> {
|
|
val elem = peek()
|
|
|
|
if (elem is None)
|
|
return elem
|
|
|
|
stack[--size] = null
|
|
|
|
if (isOneQuarterFull())
|
|
resizeArray(stack.size / RESIZE_FACTOR)
|
|
|
|
return elem
|
|
}
|
|
|
|
override fun push(elem: T) {
|
|
if (isFull())
|
|
resizeArray(size * RESIZE_FACTOR)
|
|
|
|
stack[size++] = elem
|
|
}
|
|
|
|
private fun resizeArray(capacity: Int) {
|
|
stack = stack.copyOf(capacity)
|
|
}
|
|
|
|
private fun isOneQuarterFull(): Boolean {
|
|
return size > 0 &&
|
|
size == stack.size / 4
|
|
}
|
|
|
|
override fun forEach(action: (T) -> Unit) {
|
|
for (elem in stack)
|
|
if (elem != null)
|
|
action(elem)
|
|
}
|
|
|
|
override fun <A> map(transform: (T) -> A): Stack<A> {
|
|
val transformedStack: Array<A?> = arrayOfNulls<Any>(stack.size) as Array<A?>
|
|
|
|
for (i in 0 until stack.size) {
|
|
val elem = stack[i]
|
|
if (elem == null)
|
|
transformedStack[i] = null
|
|
else
|
|
transformedStack[i] = transform(elem)
|
|
}
|
|
|
|
return ResizingArrayStack(transformedStack, size)
|
|
}
|
|
|
|
override fun clean() {
|
|
stack = arrayOfNulls<Any>(DEFAULT_CAPACITY) as Array<T?>
|
|
size = 0
|
|
}
|
|
|
|
private constructor(stack: Array<T?>, size: Int) : this() {
|
|
this.stack = stack
|
|
this.size = size
|
|
}
|
|
|
|
companion object {
|
|
const val RESIZE_FACTOR = 2
|
|
const val DEFAULT_CAPACITY = 2
|
|
}
|
|
} |