From cd9d03ecd3283019b8f8e0f18ce5c31f77a53fec Mon Sep 17 00:00:00 2001
From: Ty <ty@blahaj.land>
Date: Thu, 7 Dec 2023 23:05:21 -0700
Subject: [PATCH] Day 8 pretty chill tbh

---
 src/day8/mod.rs | 63 +++++++++++++++++++++++++++++++++++++++++++++++++
 src/main.rs     | 40 ++++++++++++++++++-------------
 2 files changed, 86 insertions(+), 17 deletions(-)
 create mode 100644 src/day8/mod.rs

diff --git a/src/day8/mod.rs b/src/day8/mod.rs
new file mode 100644
index 0000000..c389330
--- /dev/null
+++ b/src/day8/mod.rs
@@ -0,0 +1,63 @@
+use std::collections::HashMap;
+
+use crate::utils::Day;
+
+#[derive(Debug, Default)]
+pub struct Day8 {
+    pub input: String,
+}
+
+impl Day for Day8 {
+    fn part1(&mut self) -> String {
+        let (directions, map) = self.input.split_once("\n\n").unwrap();
+        let map = map.lines().map(|line| line.split_once(" = (").unwrap()).map(|(from, to)| (from, to[..to.len()-1].split_once(", ").unwrap())).collect::<HashMap<&str, (&str, &str)>>();
+
+        let mut current = "AAA";
+        let mut i = 0;
+
+        while current != "ZZZ" {
+            for direction in directions.chars() {
+                match direction {
+                    'L' => current = map[current].0,
+                    'R' => current = map[current].1,
+                    _ => panic!()
+                }
+
+                i += 1;
+
+                if current == "ZZZ" { break }
+            }
+        }
+
+        i.to_string()
+    }
+
+    fn part2(&mut self) -> String {
+        let (directions, map) = self.input.split_once("\n\n").unwrap();
+        let map = map.lines().map(|line| line.split_once(" = (").unwrap()).map(|(from, to)| (from, to[..to.len()-1].split_once(", ").unwrap())).collect::<HashMap<&str, (&str, &str)>>();
+
+        let steps = map.keys().filter(|k| k.ends_with('A')).map(|current| {
+            let mut current = *current;
+            let mut i = 0usize;
+            let mut finished = false;
+
+            while !finished {
+                for direction in directions.chars() {
+                    match direction {
+                        'L' => current = map[current].0,
+                        'R' => current = map[current].1,
+                        _ => panic!()
+                    }
+
+                    if current.ends_with('Z') { finished = true; break; }
+                }
+
+                i += 1;
+            }
+
+            i
+        }).product::<usize>() * directions.len();
+
+        steps.to_string()
+    }
+}
diff --git a/src/main.rs b/src/main.rs
index 816606c..5134f1b 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -4,10 +4,10 @@ use std::{
     time::{Duration, Instant},
 };
 
-use clap::{Parser, Subcommand};
+use clap::{Parser, Subcommand, ValueEnum};
 
 use crate::{
-    day1::Day1, day2::Day2, day3::Day3, day4::Day4, day5::Day5, day6::Day6, day7::Day7, utils::Day,
+    day1::Day1, day2::Day2, day3::Day3, day4::Day4, day5::Day5, day6::Day6, day7::Day7, day8::Day8, utils::Day,
 };
 
 pub mod day1;
@@ -17,6 +17,7 @@ pub mod day4;
 pub mod day5;
 pub mod day6;
 pub mod day7;
+pub mod day8;
 pub mod fetcher;
 pub mod utils;
 
@@ -31,6 +32,14 @@ struct Cli {
     subcommand: Subcommands,
 }
 
+#[derive(ValueEnum, Clone, PartialEq)]
+pub enum InputType {
+    Normal,
+    Example,
+    Large,
+    Custom
+}
+
 #[derive(Subcommand)]
 enum Subcommands {
     /// Solves the specified part for the specified day, after fetching the input
@@ -39,12 +48,9 @@ enum Subcommands {
         day: u8,
         /// The part to solve for
         part: u8,
-        /// If used, then the example input will be solved and checked rather than the real one
-        #[arg(short, long, group = "inputs")]
-        example: bool,
-        /// If used, then the large input will be solved and checked rather than the real one
-        #[arg(short, long, group = "inputs")]
-        large: bool,
+        /// Allows you to control the type of input used
+        #[arg(short, long)]
+        input: InputType,
     },
     /// Runs solution N amount of times, averaging speed
     Benchmark {
@@ -83,15 +89,13 @@ async fn main() {
         Subcommands::Solve {
             day,
             part,
-            example,
-            large,
+            input: input_type,
         } => {
-            let (input, solution) = match example {
-                false => match large {
-                    false => (fetcher::fetch_input(cli.auth, day).await, None),
-                    true => fetcher::fetch_large(day, part).await,
-                },
-                true => fetcher::fetch_example(cli.auth, day, part).await
+            let (input, solution) = match input_type {
+                InputType::Normal => (fetcher::fetch_input(cli.auth, day).await, None),
+                InputType::Example => fetcher::fetch_example(cli.auth, day, part).await,
+                InputType::Large => fetcher::fetch_large(day, part).await,
+                InputType::Custom => (std::fs::read_to_string({ let mut p = std::env::current_dir().unwrap(); p.push("input.txt"); p }).unwrap(), None),
             };
 
             let mut day: Box<dyn Day> = match day {
@@ -112,10 +116,11 @@ async fn main() {
                     input,
                     hands: vec![],
                 }),
+                8 => Box::new(Day8 { input }),
                 _ => panic!("Invalid day #"),
             };
             let start = std::time::Instant::now();
-            let result = day.solve(part, large);
+            let result = day.solve(part, input_type == InputType::Large);
             let end = std::time::Instant::now();
             println!("Solution: {result}");
 
@@ -168,6 +173,7 @@ async fn main() {
                     input,
                     hands: vec![],
                 }),
+                8 => Box::new(Day8 { input }),
                 _ => panic!("Invalid day #"),
             };
             let mut timings = Vec::<Duration>::new();