Added hashbrown

aoc_2024/Cargo.lock

@@ -11,6 +11,12 @@ dependencies = [
  "memchr",
 ]
 
+[[package]]
+name = "allocator-api2"
+version = "0.2.21"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "683d7910e743518b0e34f1186f92494becacb047c7b6bf616c96772180fef923"
+
 [[package]]
 name = "aoc-runner"
 version = "0.3.0"
@@ -46,6 +52,7 @@ version = "0.1.0"
 dependencies = [
  "aoc-runner",
  "aoc-runner-derive",
+ "hashbrown",
  "nom",
  "num",
  "regex",
@@ -58,6 +65,29 @@ version = "1.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ace50bade8e6234aa140d9a2f552bbee1db4d353f69b8217bc503490fc1a9f26"
 
+[[package]]
+name = "equivalent"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5443807d6dff69373d433ab9ef5378ad8df50ca6298caf15de6e52e24aaf54d5"
+
+[[package]]
+name = "foldhash"
+version = "0.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f81ec6369c545a7d40e4589b5597581fa1c441fe1cce96dd1de43159910a36a2"
+
+[[package]]
+name = "hashbrown"
+version = "0.15.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bf151400ff0baff5465007dd2f3e717f3fe502074ca563069ce3a6629d07b289"
+dependencies = [
+ "allocator-api2",
+ "equivalent",
+ "foldhash",
+]
+
 [[package]]
 name = "itoa"
 version = "1.0.14"

aoc_2024/Cargo.toml

@@ -6,6 +6,7 @@ edition = "2021"
 [dependencies]
 aoc-runner = "0.3.0"
 aoc-runner-derive = "0.3.0"
+hashbrown = "0.15.2"
 nom = "7.1.3"
 num = "0.4.3"
 regex = "1.11.1"

aoc_2024/src/day8.rs

@@ -1,4 +1,4 @@
-use std::collections::{HashMap, HashSet};
+use hashbrown::{HashMap, HashSet};
 
 use aoc_runner_derive::{aoc, aoc_generator};
 use num::integer::gcd;
@@ -15,11 +15,9 @@ fn parse(input: &str) -> Input {
             .enumerate()
             .filter(|(_, c)| c != &'.')
             .for_each(|(x, c)| {
-                if let std::collections::hash_map::Entry::Vacant(e) = map.entry(c) {
-                    e.insert(vec![(x as isize, y as isize)]);
-                } else {
-                    map.get_mut(&c).unwrap().push((x as isize, y as isize));
-                }
+                map.entry(c)
+                    .or_insert(Vec::new())
+                    .push((x as isize, y as isize));
             });
     });
     let vec = map.into_values().collect();
@@ -50,7 +48,7 @@ fn part1(input: &Input) -> usize {
 
 #[aoc(day8, part2)]
 fn part2(input: &Input) -> usize {
-    let mut set = HashSet::new();
+    let mut set = HashSet::with_capacity(input.1.len() * input.1.len());
     input.1.iter().for_each(|vec| {
         for l in 0..vec.len() {
             for r in l + 1..vec.len() {
@@ -58,7 +56,6 @@ fn part2(input: &Input) -> usize {
                 let a2 = vec[r];
                 let s = a1;
                 let v = (a2.0 - a1.0, a2.1 - a1.1);
-                let v = (v.0 / gcd(v.0, v.1), v.1 / gcd(v.0, v.1));
                 let mut d = 0;
                 loop {
                     let c = (s.0 + d * v.0, s.1 + d * v.1);
@@ -69,7 +66,7 @@ fn part2(input: &Input) -> usize {
                         break;
                     }
                 }
-                let mut d = 0;
+                let mut d = -1;
                 loop {
                     let c = (s.0 + d * v.0, s.1 + d * v.1);
                     d -= 1;
@@ -82,12 +79,6 @@ fn part2(input: &Input) -> usize {
             }
         }
     });
-    // for y in 0..input.0 .1 {
-    //     println!();
-    //     for x in 0..input.0 .0 {
-    //         print!("{}", if set.contains(&(x, y)) { '#' } else { '.' })
-    //     }
-    // }
     set.len()
 }
 
@@ -113,5 +104,7 @@ mod tests {
             )),
             34
         );
+
+        assert_eq!(part2(&parse(include_str!("../input/2024/day8.txt"))), 1017);
     }
 }