eldridge.cam
Advent of Code solutions
2021 day 17 done
+21
-10
2021/17/p1.tri
+21
-10
2021/17/p1.tri
···
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import "trilogy:parsec" use apply, parse, sep_by, string, integer
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import "trilogy:array" use collect
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import "trilogy:iterator" as it
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import "trilogy:tuple" use left, right
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import "trilogy:tuple" use right
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import "trilogy:number" use is_integer
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import "trilogy:compare" use max
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···
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rest!()
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}
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func x_at 0 _ = 0
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func x_at _ 0 = 0
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func x_at t h = h + x_at (t - 1) (h - 1)
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func in_range low high n = low <= n && n <= high
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proc main!() {
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let target and (x_min:x_max):(y_min:y_max) = parse input readall!()
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it::range 1 x_max
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|> it::flat_map (it::map ((+) 1 << left) << it::filter (in_range x_min x_max << right) << it::enumerate << h_vel x_max 0)
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|> it::flat_map (fn t.
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it::range y_min y_max
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|> it::map (fn y. (y + (t * (t - 1) / 2)) / t)
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|> it::filter is_integer
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|> it::map dbg
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let (x_min:x_max):(y_min:y_max) = parse input readall!()
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let h_candidates = it::range 1 x_max
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|> it::filter (it::any (in_range x_min x_max) << h_vel x_max 0)
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|> collect
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let v_max = it::range y_min y_max
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|> it::flat_map (fn y.
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it::range 1 1_000 # time
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|> it::map (fn t. t:(y + (t * (t - 1) / 2)) / t) # t:y velocity to hit target
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|> it::filter (right >> is_integer) # integer velocities only
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|> it::filter (fn _:v. v > 0) # also let's do upwards only
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|> it::flat_map (fn t:v. it::from h_candidates |> it::map (fn h. t:v:h))
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|> it::filter (fn t:v:h. in_range x_min x_max <| x_at t h)
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|> it::map (fn _:v:_. v)
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)
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|> it::reduce max
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|> dbg
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dbg!(v_max * (v_max + 1) / 2)
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}
+53
2021/17/p2.tri
+53
2021/17/p2.tri
···
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import "trilogy:debug" use dbg
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import "trilogy:io" use readall
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import "trilogy:core" use length
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import "trilogy:parsec" use apply, parse, sep_by, string, integer
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import "trilogy:array" use collect
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import "trilogy:set" as set
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import "trilogy:iterator" as it
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import "trilogy:tuple" use right
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import "trilogy:number" use is_integer
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proc input!() {
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apply <| string "target area: x="
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let [x_min, x_max] = apply <| sep_by (string "..") integer
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apply <| string ", y="
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let [y_min, y_max] = apply <| sep_by (string "..") integer
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return (x_min:x_max):(y_min:y_max)
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}
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func h_vel lim _ 0 = do() unit
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func h_vel lim pos vel = do() {
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let next_pos = pos + vel
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if next_pos > lim { return unit }
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yield 'next(next_pos)
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let rest = h_vel lim next_pos (vel - 1)
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rest!()
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}
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func x_at 0 _ = 0
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func x_at _ 0 = 0
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func x_at t h = h + x_at (t - 1) (h - 1)
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func in_range low high n = low <= n && n <= high
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proc main!() {
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let (x_min:x_max):(y_min:y_max) = parse input readall!()
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let h_candidates = it::range 1 x_max
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|> it::filter (it::any (in_range x_min x_max) << h_vel x_max 0)
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|> collect
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it::range y_min y_max
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|> it::flat_map (fn y.
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it::range 1 1_000 # time
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|> it::map (fn t. t:(y + (t * (t - 1) / 2)) / t) # t:y velocity to hit target
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|> it::filter (right >> is_integer) # integer velocities only
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|> it::flat_map (fn t:v. it::from h_candidates |> it::map (fn h. t:v:h))
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|> it::filter (fn t:v:h. in_range x_min x_max <| x_at t h)
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|> it::map (fn _:v:h. v:h)
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)
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|> set::collect
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|> length
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|> dbg
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}