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authorJ.J <thechairman@thechairman.info>2024-05-30 21:49:58 -0400
committerJ.J <thechairman@thechairman.info>2024-05-30 21:49:58 -0400
commit231c2b688d1e6cf0846d46e883da30e042a9c6cf (patch)
tree98a6d3a461fe190b38b2cf33a708a1d01703fa70 /aoc2023/src/day9/solve.gleam
parentfe088aa5778dcdbaab4dd8d4a7395a91c444b45c (diff)
parenta2c2b728ec6051323ed937f54816089cd2ae9d20 (diff)
downloadgleam_aoc-231c2b688d1e6cf0846d46e883da30e042a9c6cf.tar.gz
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Merge branch 'main' of https://github.com/hunkyjimpjorps/AdventOfCode
Diffstat (limited to 'aoc2023/src/day9/solve.gleam')
-rw-r--r--aoc2023/src/day9/solve.gleam70
1 files changed, 0 insertions, 70 deletions
diff --git a/aoc2023/src/day9/solve.gleam b/aoc2023/src/day9/solve.gleam
deleted file mode 100644
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--- a/aoc2023/src/day9/solve.gleam
+++ /dev/null
@@ -1,70 +0,0 @@
-import adglent.{First, Second}
-import gleam/io
-import gleam/list
-import gleam/string
-import gleam/int
-
-fn parse(input: String, backwards backwards: Bool) -> List(List(Int)) {
- use line <- list.map(string.split(input, "\n"))
- use n_str <- list.map(maybe_backwards(string.split(line, " "), backwards))
- let assert Ok(n) = int.parse(n_str)
- n
-}
-
-fn maybe_backwards(xs: List(a), backwards: Bool) -> List(a) {
- case backwards {
- False -> list.reverse(xs)
- True -> xs
- }
-}
-
-fn is_constant(ns: List(Int)) -> Bool {
- case list.unique(ns) {
- [_] -> True
- _ -> False
- }
-}
-
-fn take_derivative(ns: List(Int)) -> List(Int) {
- ns
- |> list.window_by_2
- |> list.map(fn(tup) { tup.0 - tup.1 })
-}
-
-fn extrapolate(ns: List(Int)) {
- case is_constant(ns), ns {
- True, [n, ..] -> n
- False, [n, ..] -> n + extrapolate(take_derivative(ns))
- _, _ -> panic as "list empty when it shouldn't be"
- }
-}
-
-fn part(input: String, backwards backwards: Bool) {
- input
- |> parse(backwards: backwards)
- |> list.fold(0, fn(acc, ns) { extrapolate(ns) + acc })
- |> string.inspect
-}
-
-pub fn part1(input: String) {
- part(input, backwards: False)
-}
-
-pub fn part2(input: String) {
- part(input, backwards: True)
-}
-
-pub fn main() {
- let assert Ok(part) = adglent.get_part()
- let assert Ok(input) = adglent.get_input("9")
- case part {
- First ->
- part1(input)
- |> adglent.inspect
- |> io.println
- Second ->
- part2(input)
- |> adglent.inspect
- |> io.println
- }
-}