feat(day01): day 1 solutions and initial commit

src/day01.rs

@@ -0,0 +1,93 @@
+use lazy_static::lazy_static;
+use regex::Regex;
+
+use crate::utils::digit_value;
+use crate::Day;
+
+inventory::submit! {
+    Day { number: 1, run }
+}
+
+fn first_and_last_digit(s: &str) -> usize {
+    let first = s
+        .chars()
+        .find(|c| c.is_ascii_digit())
+        .unwrap()
+        .to_digit(10)
+        .unwrap() as usize;
+    let last = s
+        .chars()
+        .rfind(|c| c.is_ascii_digit())
+        .unwrap()
+        .to_digit(10)
+        .unwrap() as usize;
+
+    first * 10 + last
+}
+
+fn day01_part1(input: &str) -> usize {
+    input.lines().map(first_and_last_digit).sum()
+}
+
+lazy_static! {
+    static ref REGEX: Regex =
+        Regex::new(r"(?P<digit>zero|one|two|three|four|five|six|seven|eight|nine|\d)").unwrap();
+}
+
+fn first_and_last_digit_regex(s: &str) -> usize {
+    let mut first_start = usize::MAX;
+    let mut last_end = 0;
+    let mut first_digit = String::new();
+    let mut last_digit = String::new();
+
+    for (index, _) in s.char_indices() {
+        if let Some(mat) = REGEX.find(&s[index..]) {
+            let match_start = index + mat.start();
+            let match_end = index + mat.end();
+
+            if match_start < first_start {
+                first_start = match_start;
+                first_digit = mat.as_str().to_string();
+            }
+            if match_end > last_end {
+                last_end = match_end;
+                last_digit = mat.as_str().to_string();
+            }
+        }
+    }
+
+    let first_digit_val = digit_value(&first_digit);
+    let last_digit_val = digit_value(&last_digit);
+
+    first_digit_val * 10 + last_digit_val
+}
+
+fn day01_part2(input: &str) -> usize {
+    input.lines().map(first_and_last_digit_regex).sum()
+}
+
+const INPUT: &str = include_str!("../data/day01.dat");
+
+fn run() {
+    println!("{}", day01_part1(INPUT));
+    println!("{}", day01_part2(INPUT));
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_day01_part1() {
+        let input = "1abc2\npqr3stu8vwx\na1b2c3d4e5f\ntreb7uchet";
+        assert_eq!(day01_part1(input), 142);
+        assert_eq!(day01_part1(INPUT), 54597);
+    }
+
+    #[test]
+    fn test_day01_part2() {
+        let input="two1nine\neightwothree\nabcone2threexyz\nxtwone3four\n4nineeightseven2\nzoneight234\n7pqrstsixteen";
+        assert_eq!(day01_part2(input), 281);
+        assert_eq!(day01_part2(INPUT), 54504);
+    }
+}