From c9bd84ebdb0bc22a134e0a5f56bedcf98e97dfd1 Mon Sep 17 00:00:00 2001
From: Quentin Boyer <quentin+dev@familleboyer.net>
Date: Wed, 10 Dec 2025 01:39:56 +0100
Subject: [PATCH] =?UTF-8?q?Use=20FX=E2=80=AFHash?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 Cargo.lock      |  7 +++++++
 Cargo.toml      |  1 +
 src/bin/day9.rs | 25 +++++++++++--------------
 3 files changed, 19 insertions(+), 14 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 84b4c38..5395d3c 100644
--- a/Cargo.lock
+++ b/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"
diff --git a/Cargo.toml b/Cargo.toml
index 0e89dad..962f7e2 100644
--- a/Cargo.toml
+++ b/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
diff --git a/src/bin/day9.rs b/src/bin/day9.rs
index b79d146..7396fe9 100644
--- a/src/bin/day9.rs
+++ b/src/bin/day9.rs
@@ -1,9 +1,6 @@
-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;
@@ -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;
@@ -203,8 +200,8 @@ fn horizontal_edges_contained(
     poly: &Polygon,
     a: Point2,
     b: Point2,
-    cache: &mut HashMap<Point2, bool>,
-    edge_cache: &mut HashMap<(u32, (u32, u32)), bool>,
+    cache: &mut FxHashMap<Point2, bool>,
+    edge_cache: &mut FxHashMap<(u32, (u32, u32)), bool>,
 ) -> bool {
     assert_ne!(a.x, b.x);
 
@@ -277,8 +274,8 @@ fn vertical_edges_contain(
     poly: &Polygon,
     a: Point2,
     b: Point2,
-    cache: &mut HashMap<Point2, bool>,
-    edge_cache: &mut HashMap<(u32, (u32, u32)), bool>,
+    cache: &mut FxHashMap<Point2, bool>,
+    edge_cache: &mut FxHashMap<(u32, (u32, u32)), bool>,
 ) -> bool {
     assert_ne!(a.y, b.y);
 
@@ -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) {