do day 3

2022/src/day_3.rs

@@ -0,0 +1,33 @@
+use std::collections::HashSet;
+
+fn get_priority(c: char) -> i32 {
+    match c {
+        'a'..='z' => c as i32 - 'a' as i32 + 1,
+        'A'..='Z' => c as i32 - 'A' as i32 + 27,
+        _ => panic!("expected letter"),
+    }
+}
+
+advent_of_code_macro::solve_problem!(
+    day 3,
+    Input Vec<String>,
+    parse |input: &str| {
+        input.lines().map(str::to_owned).collect()
+    },
+    part one |data: Input| {
+        data.iter().map(|s| {
+            let (left, right) = s.split_at(s.len() / 2);
+            let right_set: HashSet<char> = right.chars().collect();
+            get_priority(left.chars().find(|c| right_set.contains(c)).unwrap())
+        }).sum()
+    },
+    part two |data: Input| {
+        data.as_slice().chunks(3).map(|c| {
+            let second_set: HashSet<char> = c[1].chars().collect();
+            let third_set: HashSet<char> = c[2].chars().collect();
+            get_priority(c[0].chars().find(|c| second_set.contains(c) && third_set.contains(c)).unwrap())
+        }).sum()
+    },
+    sample tests [157, 70],
+    star tests [7908, 2838]
+);

2022/src/lib.rs

@@ -1,3 +1,4 @@
 #![allow(dead_code)]
 mod day_1;
 mod day_2;
+mod day_3;