solution: day 1

data/examples/01.txt

@@ -0,0 +1,10 @@
+1abc2
+pqr3stu8vwx
+a1b2c3d4e5f
+treb7uchet
+two1nine
+abcone2threexyz
+xtwone3four
+4nineeightseven2
+zoneight234
+7pqrstsixteen

src/bin/01.rs

@@ -0,0 +1,88 @@
+pub fn part_one(input: &str) -> Option<u32> {
+    let mut c = 0;
+    for line in input.lines() {
+        let mut itr = line.chars().filter(|x| x.is_ascii_digit());
+
+        let f = itr.next().unwrap();
+        let l = itr.last().unwrap_or(f);
+
+        c += format!("{f}{l}").parse::<u32>().unwrap();
+    }
+
+    Some(c)
+}
+
+pub fn part_two(input: &str) -> Option<u32> {
+    let mut c = 0;
+    let nums = [
+        "one", "two", "three", "four", "five", "six", "seven", "eight", "nine",
+    ];
+
+    for line in input.lines() {
+        let mut first = (line.len(), None);
+        let mut last = (0, None);
+
+        for (idx, n) in nums.iter().enumerate() {
+            let matches: Vec<_> = line.match_indices(n).collect();
+
+            if matches.is_empty() {
+                continue;
+            }
+
+            let m = matches.first().unwrap();
+
+            if m.0 < first.0 {
+                first = (m.0, Some(idx + 1));
+            }
+
+            let m = matches.last().unwrap();
+
+            if m.0 >= last.0 {
+                last = (m.0, Some(idx + 1));
+            }
+        }
+        let mut itr = line.chars().enumerate().filter(|(_, x)| x.is_ascii_digit());
+
+        let Some(f) = itr.next() else {
+            c += format!("{}{}", first.1.unwrap(), last.1.unwrap())
+                .parse::<u32>()
+                .unwrap();
+            continue;
+        };
+        let l = itr.last().unwrap_or(f);
+
+        if f.0 < first.0 {
+            first = (f.0, f.1.to_string().parse().ok());
+        }
+
+        if l.0 >= last.0 {
+            last = (l.0, l.1.to_string().parse().ok());
+        }
+        c += format!("{}{}", first.1.unwrap(), last.1.unwrap())
+            .parse::<u32>()
+            .unwrap();
+    }
+
+    Some(c)
+}
+
+aoc::solution!(1);
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    #[test]
+    fn test_part_one() {
+        assert_eq!(
+            part_one(&aoc::template::read_file("examples", 1)),
+            Some(351)
+        );
+    }
+    #[test]
+    fn test_part_two() {
+        assert_eq!(
+            part_two(&aoc::template::read_file("examples", 1)),
+            Some(340)
+        );
+    }
+}