diff -r c40f364d87eb -r b4def82f3f9f testing/collatz.scala --- a/testing/collatz.scala Sun Nov 05 12:56:55 2017 +0000 +++ b/testing/collatz.scala Tue Nov 07 13:08:18 2017 +0000 @@ -1,47 +1,20 @@ -// Part 1 about the 3n+1 conceture -//================================= +// Part 1 about the 3n+1 conjecture +//================================== +object CW6a { -//(1) Complete the collatz function below. It should -// recursively calculate the number of steps needed -// until the collatz series reaches the number 1. -// If needed you can use an auxilary function that -// performs the recursion. The function should expect -// arguments in the range of 1 to 1 Million. +def collatz(n: Long): Long = + if (n == 1) 1 else + if (n % 2 == 0) 1 + collatz(n / 2) else + 1 + collatz(3 * n + 1) -def collatz(n: Long): Int = - if (n == 1) 1 else - if (n % 2 == 0) (1 + collatz(n / 2)) else - (1 + collatz(3 * n + 1)) - - -//(2) Complete the collatz bound function below. It should -// calculuate how many steps are needed for each number -// from 1 upto a bound and then produce the maximum number of -// steps and the corresponding number that needs that many -// steps. You should expect bounds in the range of 1 -// upto 1 million. - -def collatz_max(bnd: Int): (Int, Int) = { - val all = for (i <- (1 to bnd).toList) yield collatz(i) +def collatz_max(bnd: Long): (Long, Long) = { + val all = for (i <- (1 to bnd.toInt).toList) yield collatz(i) val max = all.max - (all.indexOf(max) + 1, max) + (max, all.indexOf(max) + 1) } -// some testing harness -/* -val bnds = List(2, 10, 100, 1000, 10000, 100000, 77000, 90000, 1000000, 5000000) +} -for (bnd <- bnds) { - val (max, steps) = collatz_max(bnd) - println(s"In the range of 1 - ${bnd} the number ${max} needs the maximum steps of ${steps}") -} -*/ - -//val all = for (i <- (1 to 100000).toList) yield collatz1(i) -//println(all.sorted.reverse.take(10)) - - -