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);
+    }
+}

src/main.rs

@@ -0,0 +1,59 @@
+pub mod utils;
+
+// HACK: include build.rs generated file which declares modules for every dayXX.rs file found
+include!("days_mod.inc");
+
+// a struct for a single day's implementation, includes its day number and the function to run
+#[derive(Debug)]
+pub struct Day {
+    pub number: usize,
+    pub run: fn(),
+}
+
+// collects all the days registered in the inventory
+inventory::collect!(Day);
+
+// main takes one argument: 'all' or a day number
+//
+// if no argument is provided, runs the latest day
+fn main() {
+    let args: Vec<String> = std::env::args().collect();
+    match args.get(1).map(String::as_str) {
+        Some("all") => run_all_days(),
+        Some(day_str) if day_str.parse::<usize>().is_ok() => {
+            run_specific_day(day_str.parse::<usize>().unwrap())
+        }
+        None => run_latest_day(),
+        _ => println!("Invalid input. Please specify a day or 'all'."),
+    }
+}
+
+// runs the day's function, if it exists
+fn run_day(day_option: Option<&Day>) {
+    match day_option {
+        Some(day_module) => {
+            println!("Running Day: {}", day_module.number);
+            (day_module.run)();
+        }
+        None => println!("Day is not implemented yet."),
+    }
+}
+
+// runs the day with the given number
+fn run_specific_day(day: usize) {
+    let day_module = inventory::iter::<Day>().find(|d| d.number == day);
+    run_day(day_module);
+}
+
+// runs all the days in the inventory
+fn run_all_days() {
+    for day_module in inventory::iter::<Day>() {
+        run_day(Some(day_module));
+    }
+}
+
+// run the day in the inventory with the highest number
+fn run_latest_day() {
+    let latest_day = inventory::iter::<Day>().max_by_key(|d| d.number);
+    run_day(latest_day);
+}

src/utils.rs

@@ -0,0 +1,16 @@
+#[inline]
+pub fn digit_value(matched: &str) -> usize {
+    match matched {
+        "1" | "one" => 1,
+        "2" | "two" => 2,
+        "3" | "three" => 3,
+        "4" | "four" => 4,
+        "5" | "five" => 5,
+        "6" | "six" => 6,
+        "7" | "seven" => 7,
+        "8" | "eight" => 8,
+        "9" | "nine" => 9,
+        "0" | "zero" => 0,
+        _ => unreachable!(),
+    }
+}