Day 01b

day01/Cargo.toml

@@ -7,3 +7,4 @@ edition = "2021"
 aoc = { path = "../aoc" }
 color-eyre = "0.6.2"
 nom = "7.1.3"
+regex = "1.10.2"

day01/src/bin/day01a.rs

@@ -39,7 +39,7 @@ fn process(bufin: impl BufRead) -> Result<u32> {
 
 #[test]
 fn test() -> Result<()> {
-    assert_eq!(process(EXAMPLE.as_bytes())?, 142);
+    assert_eq!(process(EXAMPLE1.as_bytes())?, 142);
     Ok(())
 }
 

day01/src/bin/day01b.rs

@@ -0,0 +1,63 @@
+// Copyright (C) 2023 Leandro Lisboa Penz <lpenz@lpenz.org>
+// This file is subject to the terms and conditions defined in
+// file 'LICENSE', which is part of this source code package.
+
+use color_eyre::{eyre, Result};
+use std::io::{stdin, BufRead};
+
+use regex::Regex;
+
+use day01::*;
+
+fn readnum(s: &str) -> Result<u32> {
+    s.parse::<u32>().or(match s {
+        "zero" => Ok(0),
+        "one" => Ok(1),
+        "two" => Ok(2),
+        "three" => Ok(3),
+        "four" => Ok(4),
+        "five" => Ok(5),
+        "six" => Ok(6),
+        "seven" => Ok(7),
+        "eight" => Ok(8),
+        "nine" => Ok(9),
+        _ => Err(eyre!("invalid number")),
+    })
+}
+
+fn process(bufin: impl BufRead) -> Result<u32> {
+    let re1 = Regex::new(r"([0-9]|zero|one|two|three|four|five|six|seven|eight|nine)")?;
+    let re2 = Regex::new(r"([0-9]|enin|thgie|neves|xis|evif|ruof|eerht|owt|eno|orez)")?;
+    let lines = parser::parse(bufin)?;
+    Ok(lines
+        .into_iter()
+        .map(|line| {
+            let first = re1
+                .find(&line)
+                .ok_or_else(|| eyre!("could not match re1"))?;
+            let linerev = line.chars().rev().collect::<String>();
+            let lastrev = re2
+                .find(&linerev)
+                .ok_or_else(|| eyre!("could not match re2"))?;
+            let last = lastrev.as_str().chars().rev().collect::<String>();
+            let first = readnum(&first.as_str())?;
+            let last = readnum(&last)?;
+            let value = first * 10 + last;
+            Ok(value)
+        })
+        .collect::<eyre::Result<Vec<_>>>()?
+        .into_iter()
+        .sum())
+}
+
+#[test]
+fn test() -> Result<()> {
+    assert_eq!(process(EXAMPLE2.as_bytes())?, 281);
+    Ok(())
+}
+
+fn main() -> Result<()> {
+    color_eyre::install()?;
+    println!("{}", process(stdin().lock())?);
+    Ok(())
+}

day01/src/lib.rs

@@ -4,12 +4,21 @@
 
 pub use color_eyre::{eyre::eyre, Result};
 
-pub const EXAMPLE: &str = "1abc2
+pub const EXAMPLE1: &str = "1abc2
 pqr3stu8vwx
 a1b2c3d4e5f
 treb7uchet
 ";
 
+pub const EXAMPLE2: &str = "two1nine
+eightwothree
+abcone2threexyz
+xtwone3four
+4nineeightseven2
+zoneight234
+7pqrstsixteen
+";
+
 pub mod parser {
     use aoc::parser::*;
 
@@ -28,6 +37,7 @@ pub mod parser {
 
 #[test]
 fn test() -> Result<()> {
-    assert_eq!(parser::parse(EXAMPLE.as_bytes())?.len(), 4);
+    assert_eq!(parser::parse(EXAMPLE1.as_bytes())?.len(), 4);
+    assert_eq!(parser::parse(EXAMPLE2.as_bytes())?.len(), 7);
     Ok(())
 }