--- a/progs/collatz.scala Mon Nov 07 12:58:00 2016 +0000
+++ b/progs/collatz.scala Tue Nov 08 10:30:42 2016 +0000
@@ -1,29 +1,23 @@
-// Part 1
+// Part 1 about the 3n+1 conceture
+//=================================
-//(1)
-def collatz(n: Long): List[Long] =
- if (n == 1) List(1) else
- if (n % 2 == 0) (n::collatz(n / 2)) else
- (n::collatz(3 * n + 1))
+//(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 10 Million.
-// an alternative that calculates the steps directly
-def collatz1(n: Long): Int =
- if (n == 1) 1 else
- if (n % 2 == 0) (1 + collatz1(n / 2)) else
- (1 + collatz1(3 * n + 1))
+def collatz(n: Long): Int = ...
-//(2)
-def collatz_max(bnd: Int): Int = {
- (for (i <- 1 to bnd) yield collatz(i).length).max
-}
+//(2) Complete the collatz bound function below. It should
+// calculuate how many steps are needed for each number
+// from 1 upto a bound and return the maximum number of
+// steps. You should expect bounds in the range of 1
+// upto 10 million.
+
+def collatz_max(bnd: Int): Int = ...
-val bnds = List(10, 100, 1000, 10000, 100000, 1000000, 10000000)
-
-for (bnd <- bnds) {
- val max = collatz_max(bnd)
- println(s"In the range of 1 - ${bnd} the maximum steps are ${max}")
-}
-