add day 1, part 2

day01/part2.rs

@@ -0,0 +1,79 @@
+// Copyright 2023 Christian Ulrich
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+//
+// usage: ./part2 < input
+
+use std::io;
+
+pub struct CalibrationValues {
+    inner: Vec<u32>,
+}
+
+impl CalibrationValues {
+    pub fn from_stdin(tokens: &[(&str, u32)]) -> Result<Self, &'static str> {
+        let mut values = vec![];
+        for line in io::stdin().lines() {
+            let line = line.unwrap();
+            let mut matches = Vec::new();
+            for (token, value) in tokens.iter() {
+                match line.find(token) {
+                    Some(pos) => matches.push((pos, value)),
+                    None => (),
+                }
+                match line.rfind(token) {
+                    Some(pos) => matches.push((pos, value)),
+                    None => (),
+                }
+            }
+            if matches.len() > 0 {
+                matches.sort_by_key(|(pos, _)| *pos);
+                let first = matches.first().unwrap().1;
+                let last = matches.last().unwrap().1;
+                values.push(first * 10 + last);
+            }
+        }
+        Ok(Self { inner: values })
+    }
+
+    pub fn iter(&mut self) -> std::slice::Iter<'_, u32> {
+        self.inner.iter()
+    }
+}
+
+fn main() -> Result<(), &'static str> {
+    let tokens = [
+        ("1", 1),
+        ("2", 2),
+        ("3", 3),
+        ("4", 4),
+        ("5", 5),
+        ("6", 6),
+        ("7", 7),
+        ("8", 8),
+        ("9", 9),
+        ("one", 1),
+        ("two", 2),
+        ("three", 3),
+        ("four", 4),
+        ("five", 5),
+        ("six", 6),
+        ("seven", 7),
+        ("eight", 8),
+        ("nine", 9),
+    ];
+    let mut values = CalibrationValues::from_stdin(&tokens[..])?;
+    println!("{}", values.iter().sum::<u32>());
+    Ok(())
+}