Hailstone sequence
editable example
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ghul
use IO.Std.write_line
use Collections.LIST
use Ghul.Pipes
hailstone(n: int) -> Pipe[int] is
let current mut = n
while true do
yield current
if current == 1 then
return
fi
current =
if current % 2 == 0 then current / 2 else 3 * current + 1 fi
od
si
let sequence = hailstone(27) |> collect_list()
write_line("length of hailstone(27): {sequence.count}")
let first = sequence[0..4] |> join(", ")
let last = sequence[4..<<0] |> join(", ")
write_line("first four: {first}")
write_line("last four: {last}")
let longest mut = 0
let longest_length mut = 0
for n in 1..100_000 do
let length = hailstone(n) |> count()
if length > longest_length then
longest = n
longest_length = length
fi
od
write_line("longest under 100,000: {longest} (length {longest_length})")