Add working day2 solution

Cargo.lock

@@ -15,6 +15,7 @@ dependencies = [
 name = "day1"
 version = "0.1.0"
 dependencies = [
+ "aho-corasick",
  "regex",
 ]
 

day1/Cargo.toml

@@ -6,4 +6,5 @@ edition = "2021"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+aho-corasick = "1.1.2"
 regex = "1.10.2"

day1/src/main.rs

@@ -1,6 +1,7 @@
 mod part1;
+mod part2;
 
 fn main() {
     println!("Part1: {}", part1::main());
-    println!("Part2: TODO");
+    println!("Part2: {}", part2::main());
 }

day1/src/part1.rs

@@ -1,17 +1,17 @@
 use regex::Regex;
 
-pub(crate) fn main() -> i32 {
+pub fn main() -> i32 {
     parse(include_str!("input.txt"))
 }
 
-pub(crate) fn parse(input: &str) -> i32 {
+pub fn parse(input: &str) -> i32 {
     input
         .lines()
         .map(|m| calibration_values(num_from_line(m)))
         .sum()
 }
 
-pub(crate) fn num_from_line(line: &str) -> Vec<i32> {
+pub fn num_from_line(line: &str) -> Vec<i32> {
     Regex::new(r"(\d){1}")
         .unwrap()
         .find_iter(line)
@@ -23,7 +23,7 @@ pub(crate) fn num_from_line(line: &str) -> Vec<i32> {
         .collect()
 }
 
-pub(crate) fn calibration_values(num_vec: Vec<i32>) -> i32 {
+pub fn calibration_values(num_vec: Vec<i32>) -> i32 {
     ([num_vec[0], num_vec[num_vec.len() - 1]])
         .iter()
         .fold(String::new(), |a, b| a + &b.to_string())

day1/src/part2.rs

@@ -0,0 +1,54 @@
+use crate::part1::calibration_values;
+use aho_corasick::AhoCorasick;
+
+pub fn main() -> i32 {
+    parse(include_str!("input.txt"))
+}
+
+pub fn parse(input: &str) -> i32 {
+    input
+        .lines()
+        .map(|m| calibration_values(num_from_line(m)))
+        .sum()
+}
+
+pub fn num_from_line(line: &str) -> Vec<i32> {
+    // Convert word versions of numbers to i32, preserving order
+    let patterns = [
+        "one", "two", "three", "four", "five", "six", "seven", "eight", "nine", "1", "2", "3", "4",
+        "5", "6", "7", "8", "9",
+    ];
+    AhoCorasick::new(patterns)
+        .unwrap()
+        .find_overlapping_iter(line)
+        .map(|m| match patterns[m.pattern()] {
+            "one" => 1,
+            "two" => 2,
+            "three" => 3,
+            "four" => 4,
+            "five" => 5,
+            "six" => 6,
+            "seven" => 7,
+            "eight" => 8,
+            "nine" => 9,
+            any => any.parse().expect("Should work due to previous filtering"),
+        })
+        .collect()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn example() {
+        let input = "two1nine
+eightwothree
+abcone2threexyz
+xtwone3four
+4nineeightseven2
+zoneight234
+7pqrstsixteen";
+        assert_eq!(parse(input), 281)
+    }
+}