Catching up on days 7-9

Cargo.toml

@@ -5,6 +5,7 @@ authors = ["Olivia Kaufman <[email protected]>"]
 edition = "2021"
 
 [dependencies]
+itertools = "0.13.0"
 lazy-regex = "3.3.0"
 petgraph = "0.6.5"
 reqwest = {version = "0.12.9", features = ["blocking"]}

README.md

@@ -2,8 +2,8 @@
 
 [![Build Status](https://github.com/akaritakai/AdventOfCode2024/actions/workflows/main.yml/badge.svg)](https://github.com/akaritakai/AdventOfCode2024/actions)
 [![Code Coverage](https://img.shields.io/codecov/c/github/akaritakai/AdventOfCode2024.svg)](https://codecov.io/gh/akaritakai/AdventOfCode2024)
-![Stars](https://img.shields.io/badge/gold%20stars%20⭐-12-yellow)
-![Days Completed](https://img.shields.io/badge/days%20completed-6-green)
+![Stars](https://img.shields.io/badge/gold%20stars%20⭐-17-yellow)
+![Days Completed](https://img.shields.io/badge/days%20completed-8-green)
 
 This repo contains my Advent of Code 2024 solutions in Rust. After providing it with your puzzle inputs (or your
 session token), running the program will print out the answers to all currently solved days of the puzzle. A Docker image is provided to ensure compatibility with machines that do not want to install dependencies.
@@ -27,6 +27,11 @@ Day 05 Part 1: 5374
 Day 05 Part 2: 4260
 Day 06 Part 1: 5564
 Day 06 Part 2: 1976
+Day 07 Part 1: 20665830408335
+Day 07 Part 2: 354060705047464
+Day 08 Part 1: 359
+Day 08 Part 2: 1293
+Day 09 Part 1: 6385338159127
 ```
 
 ## Docker Instructions

src/day07.rs

@@ -0,0 +1,143 @@
+use crate::puzzle::Puzzle;
+
+pub struct Day {
+    equations: Vec<Equation>,
+}
+
+impl Puzzle for Day {
+    /// TODO
+    ///
+    /// Time complexity: TODO
+    /// Auxiliary space complexity: TODO
+    fn solve_part_1(&self) -> String {
+        let mut sum = 0;
+        for equation in &self.equations {
+            if test_equation(
+                equation.operands[0],
+                equation.test_value,
+                &equation.operands[1..],
+                false,
+            ) {
+                sum += equation.test_value;
+            }
+        }
+        sum.to_string()
+    }
+
+    /// TODO
+    ///
+    /// Time complexity: TODO
+    /// Auxiliary space complexity: TODO
+    fn solve_part_2(&self) -> String {
+        let mut sum = 0;
+        for equation in &self.equations {
+            if test_equation(
+                equation.operands[0],
+                equation.test_value,
+                &equation.operands[1..],
+                true,
+            ) {
+                sum += equation.test_value;
+            }
+        }
+        sum.to_string()
+    }
+}
+
+impl Day {
+    pub fn create(input: &str) -> Box<dyn Puzzle> {
+        let equations = input
+            .lines()
+            .map(|line| {
+                let mut parts = line.split(": ");
+                let test_value = parts.next().unwrap().parse().unwrap();
+                let operands = parts
+                    .next()
+                    .unwrap()
+                    .split_whitespace()
+                    .map(|operand| operand.parse().unwrap())
+                    .collect();
+                Equation {
+                    test_value,
+                    operands,
+                }
+            })
+            .collect();
+        Box::new(Day { equations })
+    }
+}
+
+struct Equation {
+    test_value: u64,
+    operands: Vec<u64>,
+}
+
+fn test_equation(current: u64, expected: u64, remainder: &[u64], part_2: bool) -> bool {
+    if remainder.is_empty() {
+        return current == expected;
+    }
+    if current > expected {
+        return false;
+    }
+    test_equation(current + remainder[0], expected, &remainder[1..], part_2)
+        || test_equation(current * remainder[0], expected, &remainder[1..], part_2)
+        || (part_2
+            && test_equation(
+                format!("{}{}", current, remainder[0]).parse().unwrap(),
+                expected,
+                &remainder[1..],
+                part_2,
+            ))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::path::PathBuf;
+
+    #[test]
+    fn test_part_1_example_1() {
+        let input = "\
+            190: 10 19\n\
+            3267: 81 40 27\n\
+            83: 17 5\n\
+            156: 15 6\n\
+            7290: 6 8 6 15\n\
+            161011: 16 10 13\n\
+            192: 17 8 14\n\
+            21037: 9 7 18 13\n\
+            292: 11 6 16 20";
+        let puzzle = Day::create(&input);
+        assert_eq!(puzzle.solve_part_1(), "3749");
+    }
+
+    #[test]
+    fn test_solve_part_1() {
+        let input = std::fs::read_to_string(PathBuf::from("resources/tests/07")).unwrap();
+        let puzzle = Day::create(&input);
+        assert_eq!(puzzle.solve_part_1(), "20665830408335");
+    }
+
+    #[test]
+    fn test_part_2_example_1() {
+        let input = "\
+            190: 10 19\n\
+            3267: 81 40 27\n\
+            83: 17 5\n\
+            156: 15 6\n\
+            7290: 6 8 6 15\n\
+            161011: 16 10 13\n\
+            192: 17 8 14\n\
+            21037: 9 7 18 13\n\
+            292: 11 6 16 20";
+        let puzzle = Day::create(input);
+        assert_eq!(puzzle.solve_part_2(), "11387");
+    }
+
+    #[test]
+    fn test_solve_part_2() {
+        let input = std::fs::read_to_string(PathBuf::from("resources/tests/07")).unwrap();
+        let puzzle = Day::create(&input);
+        assert_eq!(puzzle.solve_part_2(), "354060705047464");
+    }
+}