A-M baby

Task/Hailstone-sequence/Tcl/hailstone-sequence.tcl

@@ -0,0 +1,19 @@
+proc hailstone n {
+    while 1 {
+	lappend seq $n
+	if {$n == 1} {return $seq}
+	set n [expr {$n & 1 ? $n*3+1 : $n/2}]
+    }
+}
+
+set h27 [hailstone 27]
+puts "h27 len=[llength $h27]"
+puts "head4 = [lrange $h27 0 3]"
+puts "tail4 = [lrange $h27 end-3 end]"
+
+set maxlen [set max 0]
+for {set i 1} {$i<100000} {incr i} {
+    set l [llength [hailstone $i]]
+    if {$l>$maxlen} {set maxlen $l;set max $i}
+}
+puts "max is $max, with length $maxlen"