Add day22

day22/Cargo.lock

@@ -0,0 +1,119 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 4
+
+[[package]]
+name = "ahash"
+version = "0.8.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e89da841a80418a9b391ebaea17f5c112ffaaa96f621d2c285b5174da76b9011"
+dependencies = [
+ "cfg-if",
+ "getrandom",
+ "once_cell",
+ "version_check",
+ "zerocopy",
+]
+
+[[package]]
+name = "cfg-if"
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+checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
+
+[[package]]
+name = "day22"
+version = "0.1.0"
+dependencies = [
+ "ahash",
+]
+
+[[package]]
+name = "getrandom"
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+dependencies = [
+ "cfg-if",
+ "libc",
+ "wasi",
+]
+
+[[package]]
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+
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+dependencies = [
+ "unicode-ident",
+]
+
+[[package]]
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+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b5b9d34b8991d19d98081b46eacdd8eb58c6f2b201139f7c5f643cc155a633af"
+dependencies = [
+ "proc-macro2",
+]
+
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+dependencies = [
+ "proc-macro2",
+ "quote",
+ "unicode-ident",
+]
+
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+version = "0.11.0+wasi-snapshot-preview1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
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+
+[[package]]
+name = "zerocopy"
+version = "0.7.35"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1b9b4fd18abc82b8136838da5d50bae7bdea537c574d8dc1a34ed098d6c166f0"
+dependencies = [
+ "zerocopy-derive",
+]
+
+[[package]]
+name = "zerocopy-derive"
+version = "0.7.35"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fa4f8080344d4671fb4e831a13ad1e68092748387dfc4f55e356242fae12ce3e"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]

day22/Cargo.toml

@@ -0,0 +1,7 @@
+[package]
+name = "day22"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+ahash = "0.8.11"

day22/src/main.rs

@@ -0,0 +1,74 @@
+use ahash::{AHashMap, AHashSet};
+
+fn parse(input: &str) -> Vec<usize> {
+    input.lines().map(|l| l.parse().unwrap()).collect()
+}
+
+fn evolve_number(curr: &mut usize) {
+    *curr ^= *curr << 6;
+    *curr &= 0xffffff;
+    *curr ^= *curr >> 5;
+    *curr &= 0xffffff;
+    *curr ^= *curr << 11;
+    *curr &= 0xffffff;
+}
+
+fn part1(numbers: &[usize]) -> usize {
+    numbers
+        .iter()
+        .map(|secret| {
+            let mut res = *secret;
+            (0..2000).for_each(|_| evolve_number(&mut res));
+            res
+        })
+        .sum()
+}
+
+fn part2(numbers: &[usize]) -> isize {
+    // kinda slow
+    let mut sequence_bananas: AHashMap<(isize, isize, isize, isize), Vec<isize>> = AHashMap::new();
+    for number in numbers {
+        let mut costs_and_changes: Vec<(isize, isize)> = vec![];
+        let mut curr_magic = *number;
+        for _ in 0..2000 {
+            let cost = curr_magic % 10;
+            costs_and_changes.push((
+                cost as isize,
+                costs_and_changes.last().map_or(0, |l| cost as isize - l.0),
+            ));
+            evolve_number(&mut curr_magic);
+        }
+        let sequence_costs = costs_and_changes
+            .windows(4)
+            .skip(1)
+            .map(|w| ((w[0].1, w[1].1, w[2].1, w[3].1), w[3].0));
+        let mut seen_sequences = AHashSet::new();
+        for (k, v) in sequence_costs {
+            if seen_sequences.contains(&k) {
+                continue;
+            }
+            sequence_bananas
+                .entry(k)
+                .and_modify(|v2| v2.push(v))
+                .or_insert(vec![v]);
+            seen_sequences.insert(k);
+        }
+    }
+    sequence_bananas
+        .get(
+            sequence_bananas
+                .iter()
+                .max_by(|a, b| a.1.iter().sum::<isize>().cmp(&b.1.iter().sum::<isize>()))
+                .unwrap()
+                .0,
+        )
+        .unwrap()
+        .iter()
+        .sum()
+}
+
+fn main() {
+    let input = parse(include_str!("../input.txt"));
+    println!("{}", part1(&input));
+    println!("{}", part2(&input));
+}