--- 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))
-
-
-