AoC day 15, Smalltalk

#!/usr/local/bin/gst -q

init := ((stdin nextLine) subStrings: ',') collect: [:n | n asInteger].

table := LookupTable new.

(1 to: (init size - 1)) do: [ :t | table at: (init at: t) put: t ].

next := init last.
curr := 0.

(init size to: 2020) do: [ :t |
    curr := next.
    next := t - (table at: curr ifAbsent: [t]).
    table at: curr put: t.
].

stdout nextPutAll: ('Part 1: ', curr asString); nl.

(2021 to: 30000000) do: [ :t |
    (t \\ 10000 == 0) ifTrue: [ stdout nextPutAll: ('Time: ', t asString); cr; flush ].
    curr := next.
    next := t - (table at: curr ifAbsent: [t]).
    table at: curr put: t.
].

stdout nl; nextPutAll: ('Part 2: ', curr asString); nl.