2016 Update

Task/Executable-library/Io/executable-library-1.io

@@ -0,0 +1,30 @@
+HailStone := Object clone
+HailStone sequence := method(n,
+    if(n < 1, Exception raise("hailstone: expect n >= 1 not #{n}" interpolate))
+    n = n floor         // make sure integer value
+    stones := list(n)
+    while (n != 1,
+        n = if(n isEven, n/2, 3*n + 1)
+        stones append(n)
+    )
+    stones
+)
+
+if( isLaunchScript,
+    out := HailStone sequence(27)
+    writeln("hailstone(27) has length ",out size,": ",
+        out slice(0,4) join(" ")," ... ",out slice(-4) join(" "))
+
+    maxSize := 0
+    maxN := 0
+    for(n, 1, 100000-1,
+        out = HailStone sequence(n)
+        if(out size > maxSize,
+            maxSize = out size
+            maxN = n
+        )
+    )
+
+    writeln("For numbers < 100,000, ", maxN,
+    " has the longest sequence of ", maxSize, " elements.")
+)

Task/Executable-library/Io/executable-library-2.io

@@ -0,0 +1,20 @@
+counts := Map clone
+for(n, 1, 100000-1,
+    out := HailStone sequence(n)
+    key := out size asCharacter
+    counts atPut(key, counts atIfAbsentPut(key, 0) + 1)
+)
+
+maxCount := counts values max
+lengths := list()
+counts foreach(k,v,
+    if(v == maxCount, lengths append(k at(0)))
+)
+
+if(lengths size == 1,
+    writeln("The most frequent sequence length for n < 100,000 is ",lengths at(0),
+        " occurring ",maxCount," times.")
+,
+    writeln("The most frequent sequence lengths for n < 100,000 are:\n",
+        lengths join(",")," occurring ",maxCount," times each.")
+)