Mads Ager
5b9a4b289f
tailrec is no longer allowed on open functions but this test is still using it.
58 lines
1.2 KiB
Kotlin
58 lines
1.2 KiB
Kotlin
/*
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* Copyright 2010-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
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* that can be found in the LICENSE file.
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*/
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package lower.tailrec
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fun main() {
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println(add(5, 7))
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println(add(100000000, 0))
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println(fib(6))
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println(one(5))
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countdown(3)
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println(listOf(1, 2, 3).indexOf(3))
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println(listOf(1, 2, 3).indexOf(4))
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}
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tailrec fun add(x: Int, y: Int): Int = if (x > 0) add(x - 1, y + 1) else y
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fun fib(n: Int): Int {
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tailrec fun fibAcc(n: Int, acc: Int): Int = if (n < 2) {
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n + acc
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} else {
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fibAcc(n - 1, fibAcc(n - 2, acc))
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}
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return fibAcc(n, 0)
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}
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tailrec fun one(delay: Int, result: Int = delay + 1): Int = if (delay > 0) one(delay - 1) else result
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tailrec fun countdown(iterations: Int): Unit {
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if (iterations > 0) {
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println("$iterations ...")
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countdown(iterations - 1)
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} else {
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println("ready!")
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}
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}
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tailrec fun <T> List<T>.indexOf(x: T, startIndex: Int = 0): Int {
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if (startIndex >= this.size) {
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return -1
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}
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if (this[startIndex] != x) {
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return this.indexOf(x, startIndex + 1)
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}
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return startIndex
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}
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