add day 8 through 10

day10/Cargo.lock

@@ -0,0 +1,7 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 4
+
+[[package]]
+name = "day10"
+version = "0.1.0"

day10/Cargo.toml

@@ -0,0 +1,6 @@
+[package]
+name = "day10"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]

day10/src/main.rs

@@ -0,0 +1,96 @@
+use std::collections::HashMap;
+
+fn main() {
+    let input = "3113322113";
+
+    part1(input);
+}
+
+fn part1(input: &str) {
+    let mut input: Vec<_> = input.to_string().chars().collect();
+
+    for _ in 0..34 {
+        input = recurse(input);
+    }
+    for c in input {
+        print!("{c}");
+    }
+    println!();
+}
+
+fn recurse(input: Vec<char>) -> Vec<char> {
+    if input.is_empty() {
+        return input;
+    }
+
+    let mut iter = input.iter();
+    let first_digit = *iter.next().unwrap();
+
+    let s = 0;
+    let mut e = 0;
+
+    for next_digit in iter {
+        if first_digit == *next_digit {
+            e += 1
+        } else {
+            break;
+        }
+    }
+
+    let mut result = look_and_say(&input[s..=e]);
+
+    result.append(&mut recurse(input[e + 1..].to_vec()));
+
+    result
+}
+
+fn look_and_say(s: &[char]) -> Vec<char> {
+    if s.is_empty() {
+        return vec![];
+    }
+
+    let binding = s.len().to_string();
+    let length_chars = binding.chars();
+    let mut result = vec![];
+
+    for c in length_chars {
+        result.push(c);
+    }
+
+    result.push(s[0]);
+
+    result
+}
+
+#[cfg(test)]
+mod test {
+    use crate::{look_and_say, recurse};
+
+    #[test]
+    fn basic() {
+        let x = vec!['1'];
+        let result = look_and_say(&x);
+        assert_eq!(result, vec!['1', '1']);
+
+        let x = vec!['1', '1', '1'];
+        let result = look_and_say(&x);
+        assert_eq!(result, vec!['3', '1']);
+
+        let x = vec!['2'];
+        let result = look_and_say(&x);
+        assert_eq!(result, vec!['1', '2']);
+    }
+
+    #[test]
+    fn test_recurse() {
+        // let x = vec!['1'];
+        // let result = recurse(x);
+        // assert_eq!(result, vec!['1', '1']);
+
+        let result = vec!['1', '1', '1', '2', '2', '1'];
+        let result = recurse(result);
+        assert_eq!(result, vec!['3', '1', '2', '2', '1', '1']);
+    }
+}
+
+// https://adventofcode.com/2015/day/10