aoc24: init and day one solves

.gitignore

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+/target

Cargo.toml

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+[package]
+name = "aoc24"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]

readme.md

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+# AOC 2024 
+Welcome to my repository for the Advent of Code 2024. I will be solving the puzzles in Rust and posting my solutions here.
+I also keep track of my time to solve each puzzle, so I can see how I improve over time. 
+
+## Setup
+To run the solutions, you need to have Rust installed. You can install it by following the instructions on the [official website](https://www.rust-lang.org/tools/install).
+
+## Usage
+To run the solution for a specific day, use the following command:
+```bash
+cargo run <day number> <input file>
+
+# So a command to run the solution for day 1 would look like this:
+cargo run 1 input/day1.txt # or whatever the path to the input file is
+```
+
+## Progress
+- [x] Day 1 (solved in 10 minutes, 30 seconds)
+- [ ] Day 2
+- [ ] Day 3
+- [ ] Day 4
+- [ ] Day 5
+- [ ] Day 6
+- [ ] Day 7
+- [ ] Day 8
+- [ ] Day 9
+- [ ] Day 10
+- [ ] Day 11
+- [ ] Day 12
+- [ ] Day 13
+- [ ] Day 14
+- [ ] Day 15
+- [ ] Day 16
+- [ ] Day 17
+- [ ] Day 18
+- [ ] Day 19
+- [ ] Day 20
+- [ ] Day 21
+- [ ] Day 22
+- [ ] Day 23
+- [ ] Day 24
+- [ ] Day 25

src/days/day1/mod.rs

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+use std::collections::HashMap;
+use std::fs;
+
+/// Read our input file and parse it into a vector of tuples of i32
+/// Panics if the file can't be read or if the input can't be parsed
+macro_rules! read_input {
+    ($file:expr) => {
+        std::fs::read_to_string($file)
+            .unwrap()
+            .lines()
+            .map(|line| {
+                let mut parts = line.split_whitespace();
+                (
+                    parts.next().unwrap().parse().unwrap(),
+                    parts.next().unwrap().parse().unwrap(),
+                )
+            })
+            .collect::<Vec<(i32, i32)>>()
+    };
+}
+
+pub fn run(input: &str) {
+    let input = read_input!(input);
+
+    // Extract left and right lists from the input
+    let left_list: Vec<i32> = input.iter().map(|&(l, _)| l).collect();
+    let right_list: Vec<i32> = input.iter().map(|&(_, r)| r).collect();
+
+    // Calculate the total distance
+    let total_distance = calculate_total_distance(left_list.clone(), right_list.clone());
+    println!("The total distance is: {}", total_distance);
+
+    // Calculate the similarity score
+    let similarity_score = calculate_similarity_score(left_list, right_list);
+    println!("The similarity score is: {}", similarity_score);
+}
+
+fn calculate_total_distance(mut left: Vec<i32>, mut right: Vec<i32>) -> i32 {
+    // Sort both lists to pair smallest numbers with smallest numbers
+    left.sort();
+    right.sort();
+
+    // Calculate the total distance
+    let mut total_distance = 0;
+    for i in 0..left.len() {
+        total_distance += (left[i] - right[i]).abs();
+    }
+
+    total_distance
+}
+
+fn calculate_similarity_score(left: Vec<i32>, right: Vec<i32>) -> i32 {
+    // Count occurrences of each number in the right list
+    let mut right_count = HashMap::new();
+    for &num in &right {
+        *right_count.entry(num).or_insert(0) += 1;
+    }
+
+    // Calculate the similarity score
+    let mut similarity_score = 0;
+    for &num in &left {
+        let count = right_count.get(&num).unwrap_or(&0);
+        similarity_score += num * count;
+    }
+
+    similarity_score
+}

src/days/mod.rs

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+pub mod day1;

src/main.rs

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+// Use the days mod in main.rs:
+mod days;
+use crate::days::day1;
+
+fn main() {
+    // We need a day argument to know which day to run, and input for the input file
+    let args: Vec<String> = std::env::args().collect();
+    if args.len() != 3 {
+        eprintln!("Usage: {} <day> <input>", args[0]);
+        std::process::exit(1);
+    }
+
+    // Parse the day argument
+    let day = args[1].parse::<u32>().unwrap();
+    let input = &args[2];
+
+    // Run the correct day
+    match day {
+        1 => day1::run(input),
+        _ => eprintln!("Day {} not implemented yet", day),
+    }
+}