AoC 2025, day 1 (smalltalk)

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

Collection extend [ sum [ ^self inject: 0 into: [:a :b | a + b] ] ]

SequenceableCollection extend [
    " Returns collection of results from calling binBlock for each link pair "
    chain: binBlock [
        | res |
        res := self copyEmptyForCollect.
        self fold: [:curr :next | res add: (binBlock value: curr value: next). next].
        ^res
    ]
]

"
| Mainline
"
pos := 50.
stops := (stdin lines contents collect: [:line |
            | mag |
            mag := line allButFirst asNumber.
            pos := pos + (line first == $L ifTrue: [mag negated] ifFalse: [mag]).
         ]) asOrderedCollection addFirst: 50; yourself.

zeros := stops chain: [:a :b | (b > a) ifTrue:  [((a // 100) - (b // 100)) abs]
                                       ifFalse: [((a negated // 100) - (b negated // 100)) abs]].

('Part 1: %1' % {stops count: [:s | (s \\ 100) == 0]}) displayNl.
('Part 2: %1' % {zeros sum}) displayNl.