Day1

src/day1/mod.rs

@@ -0,0 +1,116 @@
+use log::debug;
+
+fn first_and_last(line: &str) -> i32 {
+    let first = line.chars().find_map(|c| c.to_digit(10)).unwrap();
+    let last = line.chars().rev().find_map(|c| c.to_digit(10)).unwrap();
+
+    let number: String = format!("{}{}", first, last);
+
+    debug!("Number: {}", number);
+
+    number.parse::<i32>().unwrap()
+}
+
+fn search_and_replace(line: &str) -> String {
+    let number_mapping = [
+        ("one", "1"),
+        ("two", "2"),
+        ("three", "3"),
+        ("four", "4"),
+        ("five", "5"),
+        ("six", "6"),
+        ("seven", "7"),
+        ("eight", "8"),
+        ("nine", "9"),
+    ];
+
+    let mut replacements: Vec<(usize, usize, &str, &str)> = Vec::new();
+
+    for (search, replace) in number_mapping {
+        let mut start = 0;
+        let mut last_pos = None;
+        while let Some(pos) = line[start..].find(search) {
+            let abs_pos = start + pos;
+            last_pos = Some(abs_pos + search.len());
+            start = abs_pos + search.len();
+        }
+
+        if let Some(last) = last_pos {
+            replacements.push((last - search.len(), last, search, replace));
+        }
+    }
+
+    // Sort by position in ascending order, excluding the last occurrences
+    replacements.sort_by(|a, b| a.0.cmp(&b.0));
+
+    let mut modified_line = line.to_string();
+
+    for (_, _, search, replace) in replacements {
+        modified_line = modified_line.replace(search, replace);
+    }
+
+    modified_line
+}
+
+pub fn day1(input: String) {
+    let result1: i32 = input
+        .lines()
+        .map(|line| -> i32 { first_and_last(line) })
+        .sum();
+
+    let result2: i32 = input
+        .lines()
+        .map(|line: &str| -> i32 {
+            let modified_line = search_and_replace(line);
+            first_and_last(&modified_line)
+        })
+        .sum();
+
+    println!("Result day 1: [{}] [{}]", result1, result2);
+}
+
+#[cfg(test)]
+mod test_day1 {
+    use crate::day1::{first_and_last, search_and_replace};
+
+    #[test]
+    fn test() {
+        let input = "two1nine
+eightwothree
+abcone2threexyz
+xtwone3four
+4nineeightseven2
+zoneight234
+7pqrstsixteen";
+
+        let mut lines: std::str::Lines<'_> = input.lines();
+        assert_eq!(
+            29,
+            first_and_last(&search_and_replace(lines.next().unwrap()))
+        );
+        assert_eq!(
+            83,
+            first_and_last(&search_and_replace(lines.next().unwrap()))
+        );
+        assert_eq!(
+            13,
+            first_and_last(&search_and_replace(lines.next().unwrap()))
+        );
+        assert_eq!(
+            24,
+            first_and_last(&search_and_replace(lines.next().unwrap()))
+        );
+        assert_eq!(
+            42,
+            first_and_last(&search_and_replace(lines.next().unwrap()))
+        );
+        assert_eq!(
+            14,
+            first_and_last(&search_and_replace(lines.next().unwrap()))
+        );
+        assert_eq!(
+            76,
+            first_and_last(&search_and_replace(lines.next().unwrap()))
+        );
+    }
+}

src/main.rs

@@ -1,3 +1,23 @@
+use std::{env, fs::read_to_string};
+
+use day1::day1;
+use log::LevelFilter;
+
+pub mod day1;
+
 fn main() {
-    println!("Hello, world!");
+    env_logger::Builder::from_default_env()
+        .filter_level(LevelFilter::Debug)
+        .init();
+
+    let args: Vec<String> = env::args().collect();
+
+    let mut day: &String = &"all".to_string();
+    if args.len() > 1 {
+        day = &args[1];
+    }
+
+    if day == &"day1".to_string() || day == &"all".to_string() {
+        day1(read_to_string("assets/day1.txt").unwrap().to_owned());
+    }
 }