day_3: basic multiplication done

src/advent_of_code/mod.rs

@@ -1,5 +1,6 @@
 mod mon_02;
 mod sun_01;
+mod tue_03;
 mod types;
 mod utils;
 
@@ -19,4 +20,11 @@ pub fn historian_hysteria() {
     // Monday 02
     let safe_report_count = mon_02::check_reports_safety("./assets/day_2_reports_input");
     println!("There are {safe_report_count} safe reports");
+
+    // Tuesday 03
+    let multiplication_added_result = tue_03::mull_it_over("./assets/day_3_instruction_input");
+    println!(
+        "The result of the sum of multiplications is {}",
+        multiplication_added_result
+    );
 }

src/advent_of_code/tue_03.rs

@@ -0,0 +1,29 @@
+use regex::Regex;
+use utils::read_instruction_input;
+
+use super::*;
+
+pub fn mull_it_over(input: &str) -> MulNumber {
+    let instruction_input = read_instruction_input(input);
+
+    // NOTE: this regex could avoid process_mul_operation by capturing the values, but seems more readable this way
+    let multiply_regex = Regex::new(r"(mul\([0-9]+,[0-9]+\))").unwrap();
+
+    let mut sum_result: MulNumber = 0;
+    for mul in multiply_regex.captures_iter(&instruction_input) {
+        let multiplication_result = process_mul_operation(&mul[1]);
+        sum_result += multiplication_result;
+    }
+
+    sum_result
+}
+
+fn process_mul_operation(operation: &str) -> MulNumber {
+    let mul_regex = Regex::new(r"mul\(([0-9]+),([0-9]+)\)").unwrap();
+
+    for values in mul_regex.captures_iter(operation) {
+        return &values[1].parse::<MulNumber>().unwrap() * &values[2].parse::<MulNumber>().unwrap();
+    }
+
+    0
+}

src/advent_of_code/types.rs

@@ -1,7 +1,9 @@
+// Historian Hysteria - Day 1
 pub type Id = i32;
 pub type Key = Id;
 pub type Similarity = Id;
 
+// Red-Nosed Reports - Day 2
 pub type Level = i32;
 pub type Report = Vec<Level>;
 pub type ReportSafety = u32;
@@ -11,3 +13,6 @@ pub enum ReportDirection {
     Increasing,
     Decreasing,
 }
+
+// Mull It Over
+pub type MulNumber = i32;

src/advent_of_code/utils.rs

@@ -32,6 +32,16 @@ pub fn read_report_list(input: &str) -> Vec<Report> {
     report_list
 }
 
+pub fn read_instruction_input(input: &str) -> String {
+    let mut instructions = String::new();
+
+    for line in read_to_string(input).unwrap().lines() {
+        instructions.push_str(line);
+    }
+
+    instructions
+}
+
 pub fn calc_distance<T>(num_1: T, num_2: T) -> T
 where
     T: PartialOrd + Sub<Output = T>,