--- a/progs/collatz_sol.scala Tue Nov 08 10:37:18 2016 +0000
+++ b/progs/collatz_sol.scala Wed Nov 09 00:52:08 2016 +0000
@@ -24,19 +24,25 @@
//(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 and the corresponding number that needs that many
// steps. You should expect bounds in the range of 1
-// upto 10 million.
+// upto 1 million.
-def collatz_max(bnd: Int): Int = {
- (for (i <- 1 to bnd) yield collatz(i).length).max
+def collatz_max(bnd: Int): (Int, Int) = {
+ val all = for (i <- (1 to bnd).toList) yield collatz(i).length
+ val max = all.max
+ (all.indexOf(max) + 1, max)
}
// some testing harness
-val bnds = List(10, 100, 1000, 10000, 100000, 1000000, 10000000)
+val bnds = List(10, 100, 1000, 10000, 100000, 1000000)
for (bnd <- bnds) {
- val max = collatz_max(bnd)
- println(s"In the range of 1 - ${bnd} the maximum steps are ${max}")
+ 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))