day 3 finished

src/day3.rs

@@ -0,0 +1,111 @@
+use itertools::Itertools;
+use std::collections::HashMap;
+use std::collections::HashSet;
+use std::fs;
+
+pub fn run() {
+    println!("Day 3:");
+    let input = fs::read_to_string("./inputs/day3.txt").expect("Could not read file");
+
+    println!("\tPart 1: {}", part1(&input));
+    println!("\tPart 2: {}", part2(&input));
+}
+
+fn part1(input: &str) -> usize {
+    let mut alphabet_map = HashMap::new();
+    let alph = "abcdefghijklmnopqrstuvwxyz";
+    for (value, letter) in format!("{}{}", alph, alph.to_uppercase())
+        .chars()
+        .enumerate()
+    {
+        alphabet_map.insert(letter, value + 1);
+    }
+
+    input
+        .split_whitespace()
+        .map(|line| {
+            let (left, right) = line.split_at(line.len() / 2);
+            assert!(left.len() == right.len());
+
+            let bag_intersection = left
+                .chars()
+                .collect::<HashSet<char>>()
+                .intersection(&right.chars().collect::<HashSet<char>>())
+                .collect::<HashSet<&char>>()
+                .into_iter()
+                .copied()
+                .collect::<Vec<char>>();
+
+            assert!(bag_intersection.len() == 1);
+
+            alphabet_map.get(&bag_intersection[0]).unwrap()
+        })
+        .sum()
+}
+fn part2(input: &str) -> usize {
+    let mut alphabet_map = HashMap::new();
+    let alph = "abcdefghijklmnopqrstuvwxyz";
+    for (value, letter) in format!("{}{}", alph, alph.to_uppercase())
+        .chars()
+        .enumerate()
+    {
+        alphabet_map.insert(letter, value + 1);
+    }
+
+    input
+        .split_whitespace()
+        .collect::<Vec<&str>>()
+        .into_iter()
+        .tuples()
+        .map(|line| {
+            let (left, mid, right) = line;
+
+            let bag_intersection = left
+                .chars()
+                .collect::<HashSet<char>>()
+                .intersection(&right.chars().collect::<HashSet<char>>())
+                .collect::<HashSet<&char>>()
+                .into_iter()
+                .copied()
+                .collect::<HashSet<char>>()
+                .intersection(&mid.chars().collect::<HashSet<char>>())
+                .collect::<HashSet<&char>>()
+                .into_iter()
+                .copied()
+                .collect::<Vec<char>>();
+
+            assert!(bag_intersection.len() == 1);
+
+            alphabet_map.get(&bag_intersection[0]).unwrap()
+        })
+        .sum()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_1() {
+        let input = "vJrwpWtwJgWrhcsFMMfFFhFp
+jqHRNqRjqzjGDLGLrsFMfFZSrLrFZsSL
+PmmdzqPrVvPwwTWBwg
+wMqvLMZHhHMvwLHjbvcjnnSBnvTQFn
+ttgJtRGJQctTZtZT
+CrZsJsPPZsGzwwsLwLmpwMDw";
+
+        assert_eq!(part1(input), 157);
+    }
+
+    #[test]
+    fn test_2() {
+        let input = "vJrwpWtwJgWrhcsFMMfFFhFp
+jqHRNqRjqzjGDLGLrsFMfFZSrLrFZsSL
+PmmdzqPrVvPwwTWBwg
+wMqvLMZHhHMvwLHjbvcjnnSBnvTQFn
+ttgJtRGJQctTZtZT
+CrZsJsPPZsGzwwsLwLmpwMDw";
+
+        assert_eq!(part2(input), 70);
+    }
+}

src/main.rs

@@ -1,7 +1,9 @@
 mod day1;
 mod day2;
+mod day3;
 fn main() {
     println!("Running Advent of Code 2022");
     day1::run();
     day2::run();
+    day3::run();
 }