fb_kotlin

fun main() {
    val n: Int = 40

    val start = System.currentTimeMillis()
    val fibs: List<Long> = fibonacci().take(n).toList()

    println(fibs)
    println(fibs.filter { it % 2 == 0L }.sum())
    println("TIME: " + ((System.currentTimeMillis() - start) / 1000.0) + "s")
}

private fun fibonacci() = sequence {
    var terms = Pair(1L, 2L)
    // this sequence is infinite
    while (true) {
        yield(terms.first)
        terms = Pair(terms.second, terms.first + terms.second)
    }
}