fibonacci.kt

package chap4.Recursion

import atomictest.eq

fun fibonacci(n: Long): Long {
  return when (n) {
    0L -> 0
    1L -> 1
    else ->
      fibonacci(n - 1) + fibonacci(n - 2)
  }
}

fun main() {
  fibonacci(0) eq 0
  fibonacci(22) eq 17711
  // Very time-consuming:
  // fibonacci(50) eq 12586269025
}