Day 1 Part 2... Feeling in agony as I can't seem to use regex to save my life. Lookahead current does not work :(

src/main.rs

@@ -16,5 +16,8 @@ fn main() -> Result<(), Box<dyn Error>>{
     println!("Day01 Part1 Test: {}", day01.part1(get_input(day01.get_day(), utils::InputType::Test)?.as_mut())?);
     println!("Day01 Part1 Result: {}", day01.part1(get_input(day01.get_day(), utils::InputType::Actual)?.as_mut())?);
 
+    println!("Day01 Part2 Test: {}", day01.part2(get_input(day01.get_day(), utils::InputType::Test)?.as_mut())?);
+    println!("Day01 Part2 Result: {}", day01.part2(get_input(day01.get_day(), utils::InputType::Actual)?.as_mut())?);
+
     Ok(())
 }

src/solutions/day01.rs

@@ -1,7 +1,22 @@
 use super::dayxx::Solution;
-use regex::Regex;
+use std::str::FromStr;
+use fancy_regex::Regex;
+use strum_macros::EnumString;
 
-const REG: &str = r#"[0-9]"#;
+#[allow(non_camel_case_types)]
+#[derive(EnumString)]
+enum WrittenNumbers {
+    zero = 0,
+    one = 1,
+    two = 2,
+    three = 3,
+    four = 4,
+    five = 5,
+    six = 6,
+    seven = 7,
+    eight = 8,
+    nine = 9
+}
 
 pub struct Day01 {}
 
@@ -10,9 +25,10 @@ impl Solution for Day01 {
         &self,
         input: &mut Vec<String>,
     ) -> Result<Box<dyn std::fmt::Display>, Box<dyn std::error::Error>> {
+        const REG: &str = r#"[0-9]"#;
         let mut total: u32 = 0;
         for line in input {
-            total += self.regex_get_num(line);
+            total += self.regex_get_num(REG, line);
         }
 
         Ok(Box::new(total))
@@ -22,7 +38,13 @@ impl Solution for Day01 {
         &self,
         input: &mut Vec<String>,
     ) -> Result<Box<dyn std::fmt::Display>, Box<dyn std::error::Error>> {
-        Ok(Box::new(0))
+        const REG: &str = r#"(?=(\d|one|two|three|four|five|six|seven|eight|nine))"#;
+        let mut total: u32 = 0;
+        for line in input {
+            total += self.regex_get_num(REG, line);
+        }
+
+        Ok(Box::new(total))
     }
 
     fn get_day(&self) -> u8 {
@@ -31,18 +53,34 @@ impl Solution for Day01 {
 }
 
 impl Day01 {
-    fn regex_get_num(&self, input: &mut String) -> u32 {
-        let re = Regex::new(REG).unwrap();
+    fn regex_get_num(&self, regex: &str, input: &mut String) -> u32 {
+        let re = Regex::new(regex).unwrap();
 
         // Get all single digits out of string
-        let matches: Vec<u32> = re
+        let matches: Vec<&str> = re
             .find_iter(input)
-            .map(|m| m.as_str().parse::<u32>().unwrap_or_default())
+            .map(|m| m.unwrap().as_str())
             .collect();
 
-        let mut num: u32 = matches.first().unwrap_or(&0) * 10;
-        num += matches.last().unwrap_or(&0);
+        // Convert everything to a number
+        let mut nums: Vec<u32> = vec![];
+        for m in matches.clone() {
+            match Day01::convert_written_number(m) {
+                Some(n) => nums.push(n),
+                None => nums.push(m.parse::<u32>().unwrap_or(0))
+            }
+        }
+
+        let mut num: u32 = nums.first().unwrap_or(&0) * 10;
+        num += nums.last().unwrap_or(&0);
 
         num
     }
+
+    fn convert_written_number(number_str: &str) -> Option<u32> {
+        match WrittenNumbers::from_str(number_str) {
+            Ok(number) => Some(number as u32),
+            Err(_) => None,
+        }
+    }
 }