From b048f5c637c836dda0bd32bf937db24fae807b6c Mon Sep 17 00:00:00 2001
From: Markus Brueckner <namenlos@geekbetrieb.de>
Date: Tue, 3 Dec 2024 16:09:31 +0100
Subject: [PATCH] Day 3

---
 2024/day3/Cargo.lock  | 54 +++++++++++++++++++++++++++++++++++++++++++
 2024/day3/Cargo.toml  |  7 ++++++
 2024/day3/src/main.rs | 51 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 112 insertions(+)
 create mode 100644 2024/day3/Cargo.lock
 create mode 100644 2024/day3/Cargo.toml
 create mode 100644 2024/day3/src/main.rs

diff --git a/2024/day3/Cargo.lock b/2024/day3/Cargo.lock
new file mode 100644
index 0000000..4c00902
--- /dev/null
+++ b/2024/day3/Cargo.lock
@@ -0,0 +1,54 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "aho-corasick"
+version = "1.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8e60d3430d3a69478ad0993f19238d2df97c507009a52b3c10addcd7f6bcb916"
+dependencies = [
+ "memchr",
+]
+
+[[package]]
+name = "day3"
+version = "0.1.0"
+dependencies = [
+ "regex",
+]
+
+[[package]]
+name = "memchr"
+version = "2.7.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "78ca9ab1a0babb1e7d5695e3530886289c18cf2f87ec19a575a0abdce112e3a3"
+
+[[package]]
+name = "regex"
+version = "1.11.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b544ef1b4eac5dc2db33ea63606ae9ffcfac26c1416a2806ae0bf5f56b201191"
+dependencies = [
+ "aho-corasick",
+ "memchr",
+ "regex-automata",
+ "regex-syntax",
+]
+
+[[package]]
+name = "regex-automata"
+version = "0.4.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "809e8dc61f6de73b46c85f4c96486310fe304c434cfa43669d7b40f711150908"
+dependencies = [
+ "aho-corasick",
+ "memchr",
+ "regex-syntax",
+]
+
+[[package]]
+name = "regex-syntax"
+version = "0.8.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2b15c43186be67a4fd63bee50d0303afffcef381492ebe2c5d87f324e1b8815c"
diff --git a/2024/day3/Cargo.toml b/2024/day3/Cargo.toml
new file mode 100644
index 0000000..0275d9d
--- /dev/null
+++ b/2024/day3/Cargo.toml
@@ -0,0 +1,7 @@
+[package]
+name = "day3"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+regex = "1.11.1"
diff --git a/2024/day3/src/main.rs b/2024/day3/src/main.rs
new file mode 100644
index 0000000..088e035
--- /dev/null
+++ b/2024/day3/src/main.rs
@@ -0,0 +1,51 @@
+use regex::Regex;
+
+fn task1() {
+    let input = std::fs::read_to_string("input.txt").unwrap();
+    let mul_inst_regex = Regex::new(r"mul\((\d{1,3}),(\d{1,3})\)").unwrap();
+
+    let sum = mul_inst_regex
+        .captures_iter(&input)
+        .fold(0, |existing, captures| {
+            let op1 = captures.get(1).unwrap();
+            let op2 = captures.get(2).unwrap();
+
+            existing + op1.as_str().parse::<i32>().unwrap() * op2.as_str().parse::<i32>().unwrap()
+        });
+
+    println!("Task 1: Sum: {}", sum);
+}
+
+fn task2() {
+    let input = std::fs::read_to_string("input.txt").unwrap();
+    let inst_regex = Regex::new(r"mul\((\d{1,3}),(\d{1,3})\)|do\(\)|don't\(\)").unwrap();
+
+    let mut sum = 0;
+    let mut is_enabled = true;
+    for instruction in inst_regex.captures_iter(&input) {
+        match instruction.get(0).and_then(|m| Some(m.as_str())) {
+            Some("do()") => {
+                is_enabled = true;
+            }
+            Some("don't()") => {
+                is_enabled = false;
+            }
+            Some(_) => {
+                if is_enabled {
+                    let op1 = instruction.get(1).unwrap();
+                    let op2 = instruction.get(2).unwrap();
+
+                    sum +=
+                        op1.as_str().parse::<i32>().unwrap() * op2.as_str().parse::<i32>().unwrap()
+                }
+            }
+            None => panic!("No clue, what I matched!"),
+        }
+    }
+    println!("Task 2: Sum: {}", sum);
+}
+
+fn main() {
+    task1();
+    task2();
+}