Advent 2023 Day 7, 8 & 9

advent_of_code_2023/day8/main1.rs

@@ -0,0 +1,39 @@
+use std::{fs::read_to_string, collections::HashMap};
+
+fn parse_input() -> (String, HashMap<String, (String, String)>) {
+    let lines = read_to_string("input.txt").unwrap().lines().map(|line| {
+        String::from(line)
+    }).collect::<Vec<_>>();
+
+    let instr = lines[0].trim();
+    let mut mapping: HashMap<String, (String, String)> = HashMap::new();
+
+    for line in &lines[2..] {
+        let (key, instructions) = line.split_once('=').unwrap();
+        let (left, right) = instructions.trim().split_once(' ').unwrap();
+        mapping.insert(String::from(key.trim()), (String::from(&left[1..4]), String::from(&right[..3])));
+    }
+
+    (String::from(instr), mapping)
+}
+
+fn main() {
+    let (instructions, mapping) = parse_input();
+    
+    let mut position = String::from("AAA");
+    let mut steps = 0;
+    let mut caret = 0;
+
+    loop {
+        if position == "ZZZ" {
+            break;
+        }
+
+        position = if instructions.as_bytes()[caret] == b'L' { mapping[&position].0.clone() } else {mapping[&position].1.clone() };
+        caret = if caret + 1 == instructions.len() { 0 } else { caret +  1 };
+        steps += 1;
+    }
+
+    println!("Number of steps taken: {}", steps);
+
+}