From e8f3ca5355964d7aaae55686559fb8d742b804d5 Mon Sep 17 00:00:00 2001
From: Patrick Auernig <patrick.auernig@mykolab.com>
Date: Tue, 3 Dec 2024 21:22:36 +0100
Subject: [PATCH] Add solution for 2024 day 03 part 2

---
 2024/day-03/parser.rs   | 62 ++++++++++++++++++++++-------------------
 2024/day-03/part_one.rs |  7 ++---
 2024/day-03/part_two.rs | 19 +++++++++++++
 2024/day-03/sample2.txt |  1 +
 4 files changed, 56 insertions(+), 33 deletions(-)
 create mode 100644 2024/day-03/part_two.rs
 create mode 100644 2024/day-03/sample2.txt

diff --git a/2024/day-03/parser.rs b/2024/day-03/parser.rs
index a1509c2..8e0a9ff 100644
--- a/2024/day-03/parser.rs
+++ b/2024/day-03/parser.rs
@@ -1,67 +1,71 @@
+#![allow(dead_code)]
+
 use std::fs;
 use std::path::Path;
 
 
 #[derive(Debug)]
-pub enum Instruction {
-    Mul(u64, u64),
-}
-
-
-#[derive(Debug)]
-pub enum ParserState {
+enum ParserState {
     ParseAny,
-    ParseIdent(Ident),
+    ParseMul(u32),
+    ParseDo(u32),
+    ParseDont(u32),
+    ParserEnableMul(bool),
     ParseNumber(u32, [Vec<u32>; 2]),
 }
 
 
-#[derive(Debug)]
-pub enum Ident {
-    Mul(u32),
-}
-
-
 #[derive(Debug)]
 pub struct PuzzleInput {
-    pub instructions: Vec<Instruction>,
+    pub instructions: Vec<(u64, u64)>,
 }
 
 impl PuzzleInput {
-    pub fn parse<P>(path: P) -> Self
+    pub fn parse<P>(path: P, use_cond: bool) -> Self
     where
         P: AsRef<Path>,
     {
         let content = fs::read_to_string(path).unwrap();
         let mut instructions = Vec::new();
 
+        let mut parse_mul = true;
         let mut state = ParserState::ParseAny;
 
         for ch in content.chars() {
             state = match (ch, state) {
-                ('m', ParserState::ParseIdent(Ident::Mul(0)) | ParserState::ParseAny) => {
-                    ParserState::ParseIdent(Ident::Mul(1))
+                ('m', ParserState::ParseMul(0) | ParserState::ParseAny) if parse_mul => {
+                    ParserState::ParseMul(1)
                 }
-                ('u', ParserState::ParseIdent(Ident::Mul(1))) => {
-                    ParserState::ParseIdent(Ident::Mul(2))
-                }
-                ('l', ParserState::ParseIdent(Ident::Mul(2))) => {
-                    ParserState::ParseIdent(Ident::Mul(3))
-                }
-                ('(', ParserState::ParseIdent(Ident::Mul(3))) => {
-                    ParserState::ParseNumber(0, [vec![], vec![]])
-                }
-                (',', ParserState::ParseNumber(0, nums)) => ParserState::ParseNumber(1, nums),
+                ('u', ParserState::ParseMul(1)) => ParserState::ParseMul(2),
+                ('l', ParserState::ParseMul(2)) => ParserState::ParseMul(3),
+                ('(', ParserState::ParseMul(3)) => ParserState::ParseNumber(0, [vec![], vec![]]),
                 (')', ParserState::ParseNumber(1, nums)) => {
                     let nums = numbers_from_slice(&nums);
-                    instructions.push(Instruction::Mul(nums[0], nums[1]));
+                    instructions.push((nums[0], nums[1]));
                     ParserState::ParseAny
                 }
+                (',', ParserState::ParseNumber(0, nums)) => ParserState::ParseNumber(1, nums),
                 ('0'..='9', ParserState::ParseNumber(n, mut nums)) => {
                     let digit = ch.to_digit(10).unwrap();
                     nums[n as usize].push(digit);
                     ParserState::ParseNumber(n, nums)
                 }
+
+                ('d', ParserState::ParseDo(0) | ParserState::ParseAny) if use_cond => {
+                    ParserState::ParseDo(1)
+                }
+                ('o', ParserState::ParseDo(1)) => ParserState::ParseDo(2),
+                ('n', ParserState::ParseDo(2)) => ParserState::ParseDont(0),
+                ('\'', ParserState::ParseDont(0)) => ParserState::ParseDont(1),
+                ('t', ParserState::ParseDont(1)) => ParserState::ParseDont(2),
+
+                ('(', ParserState::ParseDo(2)) => ParserState::ParserEnableMul(true),
+                ('(', ParserState::ParseDont(2)) => ParserState::ParserEnableMul(false),
+                (')', ParserState::ParserEnableMul(cond)) => {
+                    parse_mul = cond;
+                    ParserState::ParseAny
+                }
+
                 _ => ParserState::ParseAny,
             }
         }
diff --git a/2024/day-03/part_one.rs b/2024/day-03/part_one.rs
index d4d4fbf..51b726b 100644
--- a/2024/day-03/part_one.rs
+++ b/2024/day-03/part_one.rs
@@ -2,17 +2,16 @@ mod parser;
 
 use std::env;
 
-use parser::{Instruction, PuzzleInput};
+use parser::PuzzleInput;
 
 
 fn main() {
     let input_file = env::args().nth(1).expect("file name required");
 
-    let input = PuzzleInput::parse(input_file);
+    let input = PuzzleInput::parse(input_file, false);
 
     let mut sum: u64 = 0;
-    for instr in input.instructions {
-        let Instruction::Mul(a, b) = instr;
+    for (a, b) in input.instructions {
         sum += a * b;
     }
 
diff --git a/2024/day-03/part_two.rs b/2024/day-03/part_two.rs
new file mode 100644
index 0000000..32fe69c
--- /dev/null
+++ b/2024/day-03/part_two.rs
@@ -0,0 +1,19 @@
+mod parser;
+
+use std::env;
+
+use parser::PuzzleInput;
+
+
+fn main() {
+    let input_file = env::args().nth(1).expect("file name required");
+
+    let input = PuzzleInput::parse(input_file, true);
+
+    let mut sum: u64 = 0;
+    for (a, b) in input.instructions {
+        sum += a * b;
+    }
+
+    println!("{sum}");
+}
diff --git a/2024/day-03/sample2.txt b/2024/day-03/sample2.txt
new file mode 100644
index 0000000..b774ec9
--- /dev/null
+++ b/2024/day-03/sample2.txt
@@ -0,0 +1 @@
+xmul(2,4)&mul[3,7]!^don't()_mul(5,5)+mul(32,64](mul(11,8)undo()?mul(8,5))
\ No newline at end of file