From dc67b38420bfe37c0136448e4180a17a17ffe513 Mon Sep 17 00:00:00 2001
From: Keenan Tims <ktims@gotroot.ca>
Date: Wed, 4 Dec 2024 16:39:57 -0800
Subject: [PATCH] day3: disable unicode matching, don't recompile RE for every
 iteration

---
 3/Cargo.lock  | 17 +++++++++++++++++
 3/Cargo.toml  |  3 ++-
 3/src/main.rs | 18 ++++++++++--------
 3 files changed, 29 insertions(+), 9 deletions(-)

diff --git a/3/Cargo.lock b/3/Cargo.lock
index 4c00902..918bc6f 100644
--- a/3/Cargo.lock
+++ b/3/Cargo.lock
@@ -15,6 +15,7 @@ dependencies = [
 name = "day3"
 version = "0.1.0"
 dependencies = [
+ "nom",
  "regex",
 ]
 
@@ -24,6 +25,22 @@ version = "2.7.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "78ca9ab1a0babb1e7d5695e3530886289c18cf2f87ec19a575a0abdce112e3a3"
 
+[[package]]
+name = "minimal-lexical"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "68354c5c6bd36d73ff3feceb05efa59b6acb7626617f4962be322a825e61f79a"
+
+[[package]]
+name = "nom"
+version = "7.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d273983c5a657a70a3e8f2a01329822f3b8c8172b73826411a55751e404a0a4a"
+dependencies = [
+ "memchr",
+ "minimal-lexical",
+]
+
 [[package]]
 name = "regex"
 version = "1.11.1"
diff --git a/3/Cargo.toml b/3/Cargo.toml
index 0275d9d..2b7e6ab 100644
--- a/3/Cargo.toml
+++ b/3/Cargo.toml
@@ -4,4 +4,5 @@ version = "0.1.0"
 edition = "2021"
 
 [dependencies]
-regex = "1.11.1"
+nom = "7.1.3"
+regex = { version = "1.11.1", default-features = false, features = ["perf", "std"] }
diff --git a/3/src/main.rs b/3/src/main.rs
index 3347003..3b5af1c 100644
--- a/3/src/main.rs
+++ b/3/src/main.rs
@@ -1,4 +1,4 @@
-use regex::Regex;
+use regex::bytes::Regex;
 use std::fs::File;
 use std::io::{BufRead, BufReader, Lines};
 use std::time::{Duration, Instant};
@@ -39,10 +39,11 @@ fn main() {
 
 fn problem1<T: BufRead>(input: Lines<T>) -> u64 {
     let mut sum = 0u64;
+    let re = Regex::new(r"(?-u)mul\((\d+),(\d+)\)").unwrap();
     for line in input.map(|i| i.unwrap()) {
-        let re = Regex::new(r"mul\((\d+),(\d+)\)").unwrap();
-        for m in re.captures_iter(&line) {
-            sum += m[1].parse::<u64>().unwrap() * m[2].parse::<u64>().unwrap();
+        let line = line.as_bytes();
+        for m in re.captures_iter(line) {
+            sum +=  std::str::from_utf8(&m[1]).unwrap().parse::<u64>().unwrap() * std::str::from_utf8(&m[2]).unwrap().parse::<u64>().unwrap();
         }
     }
     sum
@@ -52,13 +53,14 @@ fn problem1<T: BufRead>(input: Lines<T>) -> u64 {
 fn problem2<T: BufRead>(input: Lines<T>) -> u64 {
     let mut sum = 0u64;
     let mut do_mul = true;
+    let re = Regex::new(r"(?-u)(do\(\)|don't\(\)|mul\((\d+),(\d+)\))").unwrap();
     for line in input.map(|i| i.unwrap()) {
-        let re = Regex::new(r"(do\(\)|don't\(\)|mul\((\d+),(\d+)\))").unwrap();
-        for m in re.captures_iter(&line) {
-            match &m[1] {
+        let line = line.as_bytes();
+        for m in re.captures_iter(line) {
+            match std::str::from_utf8(&m[1]).unwrap() {
                 "do()" => do_mul = true,
                 "don't()" => do_mul = false,
-                _ if do_mul => sum += m[2].parse::<u64>().unwrap() * m[3].parse::<u64>().unwrap(),
+                _ if do_mul => sum += std::str::from_utf8(&m[2]).unwrap().parse::<u64>().unwrap() * std::str::from_utf8(&m[3]).unwrap().parse::<u64>().unwrap(),
                 _ => {}
             }
         }