RosettaCodeData/Task/Van-Eck-sequence/Kotlin/van-eck-sequence.kts

24 lines
619 B
Kotlin

fun main() {
println("First 10 terms of Van Eck's sequence:")
vanEck(1, 10)
println("")
println("Terms 991 to 1000 of Van Eck's sequence:")
vanEck(991, 1000)
}
private fun vanEck(firstIndex: Int, lastIndex: Int) {
val vanEckMap = mutableMapOf<Int, Int>()
var last = 0
if (firstIndex == 1) {
println("VanEck[1] = 0")
}
for (n in 2..lastIndex) {
val vanEck = if (vanEckMap.containsKey(last)) n - vanEckMap[last]!! else 0
vanEckMap[last] = n
last = vanEck
if (n >= firstIndex) {
println("VanEck[$n] = $vanEck")
}
}
}