Use FX Hash

Cargo.lock

@@ -76,6 +76,7 @@ dependencies = [
  "clap",
  "color-eyre",
  "humantime",
+ "rustc-hash",
 ]
 
 [[package]]
@@ -319,6 +320,12 @@ version = "0.1.26"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "56f7d92ca342cea22a06f2121d944b4fd82af56988c270852495420f961d4ace"
 
+[[package]]
+name = "rustc-hash"
+version = "2.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "357703d41365b4b27c590e3ed91eabb1b663f07c4c084095e60cbed4362dff0d"
+
 [[package]]
 name = "serde"
 version = "1.0.228"

Cargo.toml

@@ -10,6 +10,7 @@ bstr = "1.11.0"
 clap = { version = "4.5.21", features = ["derive"] }
 color-eyre = "0.6.3"
 humantime = "2.1.0"
+rustc-hash = "2.1.1"
 
 [profile.release]
 debug = true

src/bin/day9.rs

@@ -1,17 +1,14 @@
-use std::{
-    collections::{HashMap, HashSet},
-    hash::Hash,
-    ops::RangeInclusive,
-    time::Instant,
-};
+use std::{collections::HashSet, hash::Hash, ops::RangeInclusive, time::Instant};
+
+use rustc_hash::FxHashMap;
 
 use aoc_2025::{load, print_res};
 use bstr::BString;
 
 #[derive(PartialEq, Eq, Hash, Debug, Clone, Copy)]
 pub struct Point2 {
-    x: u64,
-    y: u64,
+    x: u32,
+    y: u32,
 }
 
 type Parsed = Vec<Point2>;
@@ -32,7 +29,7 @@ pub fn parsing(input: &BString) -> color_eyre::Result<Parsed> {
         .collect()
 }
 
-fn rect_area(a: &Point2, b: &Point2) -> u64 {
+fn rect_area(a: &Point2, b: &Point2) -> u32 {
     (a.x.abs_diff(b.x) + 1) * (a.y.abs_diff(b.y) + 1)
 }
 
@@ -52,11 +49,11 @@ pub fn part1(input: Parsed) {
 struct Polygon {
     points: Vec<Point2>,
 
-    x_values: Vec<u64>,
-    y_values: Vec<u64>,
+    x_values: Vec<u32>,
+    y_values: Vec<u32>,
 
-    vertical_edges_by_x_slot: Vec<Vec<RangeInclusive<u64>>>,
-    horizontal_edges_by_y_slot: Vec<Vec<RangeInclusive<u64>>>,
+    vertical_edges_by_x_slot: Vec<Vec<RangeInclusive<u32>>>,
+    horizontal_edges_by_y_slot: Vec<Vec<RangeInclusive<u32>>>,
 }
 
 impl Polygon {
@@ -167,11 +164,11 @@ impl Polygon {
         &self.points
     }
 
-    pub fn x_values(&self) -> &[u64] {
+    pub fn x_values(&self) -> &[u32] {
         &self.x_values
     }
 
-    pub fn y_values(&self) -> &[u64] {
+    pub fn y_values(&self) -> &[u32] {
         &self.y_values
     }
 
@@ -184,7 +181,7 @@ impl Polygon {
     }
 }
 
-struct InsertGuard<'a, K, V>(K, V, &'a mut HashMap<K, V>)
+struct InsertGuard<'a, K, V>(K, V, &'a mut FxHashMap<K, V>)
 where
     K: Hash + Eq + Copy,
     V: Copy;
@@ -203,15 +200,15 @@ fn horizontal_edges_contained(
     poly: &Polygon,
     a: Point2,
     b: Point2,
-    cache: &mut HashMap<Point2, bool>,
-    edge_cache: &mut HashMap<(u64, (u64, u64)), bool>,
+    cache: &mut FxHashMap<Point2, bool>,
+    edge_cache: &mut FxHashMap<(u32, (u32, u32)), bool>,
 ) -> bool {
     assert_ne!(a.x, b.x);
 
     let min_x = a.x.min(b.x);
     let max_x = a.x.max(b.x);
 
-    let y_values: &[u64] = if a.y == b.y { &[a.y] } else { &[a.y, b.y] };
+    let y_values: &[u32] = if a.y == b.y { &[a.y] } else { &[a.y, b.y] };
 
     let mut contains = |point: Point2| match cache.get(&point) {
         Some(&v) => v,
@@ -277,15 +274,15 @@ fn vertical_edges_contain(
     poly: &Polygon,
     a: Point2,
     b: Point2,
-    cache: &mut HashMap<Point2, bool>,
-    edge_cache: &mut HashMap<(u64, (u64, u64)), bool>,
+    cache: &mut FxHashMap<Point2, bool>,
+    edge_cache: &mut FxHashMap<(u32, (u32, u32)), bool>,
 ) -> bool {
     assert_ne!(a.y, b.y);
 
     let min_y = a.y.min(b.y);
     let max_y = a.y.max(b.y);
 
-    let x_values: &[u64] = if a.x == b.x { &[a.x] } else { &[a.x, b.x] };
+    let x_values: &[u32] = if a.x == b.x { &[a.x] } else { &[a.x, b.x] };
 
     let mut contains = |point: Point2| match cache.get(&point) {
         Some(&v) => v,
@@ -353,9 +350,9 @@ pub fn part2(input: Parsed) {
 
     let mut max_area = 0;
 
-    let mut contains_cache = HashMap::new();
-    let mut h_edge_cache = HashMap::new();
-    let mut v_edge_cache = HashMap::new();
+    let mut contains_cache = FxHashMap::default();
+    let mut h_edge_cache = FxHashMap::default();
+    let mut v_edge_cache = FxHashMap::default();
 
     for (ia, &a) in poly.points().iter().enumerate() {
         for &b in poly.points().iter().skip(ia + 1) {