Day 1

.gitignore

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+/target

Cargo.lock

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+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "advent_of_code_2023"
+version = "0.1.0"

Cargo.toml

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+[package]
+name = "advent_of_code_2023"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

src/day1/mod.rs

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+
+pub enum PART {
+    ONE,
+    TWO
+}
+
+fn line_to_calibration_part1(line: &str) -> (Option<u32>, Option<u32>) {
+    let a = line.chars().find(|c| c.is_ascii_digit()).expect("Could not find a valid number from the left").to_digit(10);
+    let b = line.chars().rev().find(|c| c.is_ascii_digit()).expect("Could not find a valid number from the right").to_digit(10);
+
+    (a, b)
+}
+
+fn line_to_calibration_part2(line: &str) -> (Option<u32>, Option<u32>) {
+
+    let digits_words = &["one", "two", "three", "four", "five", "six", "seven", "eight", "nine"];
+
+    let mut a: Option<u32> = None;
+    let mut b: Option<u32> = None;
+
+
+    'search: for i in 0..line.len() {
+        let (_, remaining_line) = line.split_at(i);
+        for (j, word) in digits_words.iter().enumerate() {
+            if remaining_line.starts_with(word) {
+                a = Some(j as u32 + 1);
+                break 'search;
+            }else if let Some(char) = remaining_line.chars().next() && char.is_numeric() {
+                a = char.to_digit(10);
+                break 'search;
+            }
+        }
+    }
+
+    'search: for i in 0..line.len() {
+        let (remaining_line, _) = line.split_at(line.len() - i);
+        for (j, word) in digits_words.iter().enumerate() {
+            if remaining_line.ends_with(word) {
+                b = Some(j as u32 + 1);
+                break 'search;
+            }else if let Some(char) = remaining_line.chars().last() && char.is_numeric() {
+                b = char.to_digit(10);
+                break 'search;
+            }
+        }
+    }
+
+    (a,b)
+}
+
+pub fn solve(lines: Vec<String>, part: self::PART) -> u32 {
+    let mut sum = 0;
+    for line in lines.iter() {
+        let (a, b) = match part {
+            PART::ONE => line_to_calibration_part1(line),
+            PART::TWO => line_to_calibration_part2(line)
+        };
+        if let (Some(a), Some(b)) = (a, b) {
+            sum +=  a * 10 + b;
+        }
+    }
+    sum
+}

src/main.rs

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+#![feature(let_chains)]
+
+mod day1;
+mod utils;
+
+
+fn main() {
+    let day1_data_path = "./datasets/adventofcode.com_2023_day_1_input.txt";
+    let day1_result_part1 = day1::solve(utils::lines_from_file(day1_data_path).expect("Could not load the dataset for day 1"), day1::PART::ONE);
+    let day1_result_part2 = day1::solve(utils::lines_from_file(day1_data_path).expect("Could not load the dataset for day 1"), day1::PART::TWO);
+
+    println!("Day 1 (part 1) result is {}", day1_result_part1);
+    println!("Day 1 (part 2) result is {}", day1_result_part2);
+}
+
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    
+    #[test]
+    fn day1() {
+        let day1_data_path = "./datasets/adventofcode.com_2023_day_1_input.txt";
+        let day1_result_part1 = day1::solve(utils::lines_from_file(day1_data_path).expect("Could not load the dataset for day 1"), day1::PART::ONE);
+        let day1_result_part2 = day1::solve(utils::lines_from_file(day1_data_path).expect("Could not load the dataset for day 1"), day1::PART::TWO);
+
+        assert_eq!(day1_result_part1, 54338);
+        assert_eq!(day1_result_part2, 53389);
+    }
+}

src/utils.rs

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+use std::{
+    fs::File,
+    io::{prelude::*, BufReader,Result},
+    path::Path,
+};
+
+pub fn lines_from_file(filename: impl AsRef<Path>) -> Result<Vec<String>> {
+    let file = File::open(filename)?;
+
+    let buf = BufReader::new(file);
+    buf.lines().collect()
+}