Enforce usage of FxHash

Cargo.toml

@@ -17,3 +17,4 @@ test_lib = []
 gcd = "2.3.0"
 itertools = "0.12.0"
 pico-args = "0.5.0"
+rustc-hash = { version = "1.1.0", features = [] }

README.md

@@ -11,16 +11,16 @@ Solutions for [Advent of Code](https://adventofcode.com/) in [Rust](https://www.
 
 | Day | Part 1 | Part 2 |
 | :---: | :---: | :---:  |
-| [Day 1](./src/bin/01.rs) | `70.9µs` | `848.4µs` |
-| [Day 2](./src/bin/02.rs) | `37.7µs` | `48.4µs` |
-| [Day 3](./src/bin/03.rs) | `500.7µs` | `487.2µs` |
-| [Day 4](./src/bin/04.rs) | `238.1µs` | `239.4µs` |
-| [Day 5](./src/bin/05.rs) | `20.5µs` | `74.7µs` |
-| [Day 6](./src/bin/06.rs) | `456.0ns` | `385.0ns` |
-| [Day 7](./src/bin/07.rs) | `289.8µs` | `291.3µs` |
-| [Day 8](./src/bin/08.rs) | `506.5µs` | `3.3ms` |
-
-**Total: 6.95ms**
+| [Day 1](./src/bin/01.rs) | `69.8µs` | `847.4µs` |
+| [Day 2](./src/bin/02.rs) | `38.2µs` | `49.6µs` |
+| [Day 3](./src/bin/03.rs) | `231.7µs` | `245.9µs` |
+| [Day 4](./src/bin/04.rs) | `199.2µs` | `195.5µs` |
+| [Day 5](./src/bin/05.rs) | `20.2µs` | `74.1µs` |
+| [Day 6](./src/bin/06.rs) | `489.0ns` | `399.0ns` |
+| [Day 7](./src/bin/07.rs) | `287.6µs` | `287.9µs` |
+| [Day 8](./src/bin/08.rs) | `274.1µs` | `1.6ms` |
+
+**Total: 4.42ms**
 <!--- benchmarking table --->
 
 ---

clippy.toml

@@ -0,0 +1 @@
+disallowed-types = ["std::collections::HashMap", "std::collections::HashSet"]

src/bin/03.rs

@@ -1,5 +1,5 @@
 use itertools::Itertools;
-use std::collections::{HashMap, HashSet};
+use rustc_hash::{FxHashMap as HashMap, FxHashSet as HashSet };
 advent_of_code::solution!(3);
 
 #[derive(Debug)]

src/bin/04.rs

@@ -1,4 +1,4 @@
-use std::collections::HashSet;
+use rustc_hash::FxHashSet as HashSet;
 advent_of_code::solution!(4);
 
 fn number_of_winning_numbers_per_game(input: &str) -> impl Iterator<Item = usize> + '_ {

src/bin/08.rs

@@ -1,5 +1,5 @@
 use gcd::Gcd;
-use std::collections::HashMap;
+use rustc_hash::FxHashMap as HashMap;
 advent_of_code::solution!(8);
 
 #[derive(Copy, Clone, Debug)]