1 files changed, 59 insertions, 0 deletions
diff --git a/aoc22/day3/src/main.rs b/aoc22/day3/src/main.rs
new file mode 100644
index 0000000..81a3fe7
--- /dev/null
+++ b/aoc22/day3/src/main.rs
@@ -0,0 +1,59 @@
+#![feature(iter_next_chunk)]
+
+use std::collections::HashSet;
+
+fn main() {
+    part1();
+    part2();
+}
+
+fn part1() {
+    let input = include_str!("../input");
+
+    let ans: u32 = input.lines().map(|line| {
+        let first = &line[..line.len()/2];
+        let second = &line[line.len()/2..];
+        let first: HashSet<char> = first.chars().collect();
+        let second: HashSet<char> = second.chars().collect();
+        let common = *first.intersection(&second).next().unwrap();
+        let priority = match common {
+            'a'..='z' => 1 + common as u32 - 'a' as u32,
+            'A'..='Z' => 27 + common as u32 - 'A' as u32,
+            _ => unreachable!(),
+        };
+
+        priority
+    }).sum();
+
+    println!("{}", ans);
+}
+
+fn part2() {
+    let input = include_str!("../input");
+
+    let mut lines = input.lines();
+
+    let mut sum = 0;
+    while let Ok([first, second, third]) = lines.next_chunk::<3>() {
+        let first: HashSet<char> = first.chars().collect();
+        let second: HashSet<char> = second.chars().collect();
+        let third: HashSet<char> = third.chars().collect();
+        let common = *first
+            .intersection(&second)
+            .copied()
+            .collect::<HashSet<char>>()
+            .intersection(&third)
+            .next()
+            .unwrap();
+
+        let priority = match common {
+            'a'..='z' => 1 + common as u32 - 'a' as u32,
+            'A'..='Z' => 27 + common as u32 - 'A' as u32,
+            _ => unreachable!(),
+        };
+
+        sum += priority;
+    }
+
+    println!("{}", sum);
+}