pt 2

.gitignore

@@ -1,14 +1,14 @@
-# Generated by Cargo
-# will have compiled files and executables
-debug/
-target/
-
-# Remove Cargo.lock from gitignore if creating an executable, leave it for libraries
-# More information here https://doc.rust-lang.org/cargo/guide/cargo-toml-vs-cargo-lock.html
-Cargo.lock
-
-# These are backup files generated by rustfmt
-**/*.rs.bk
-
-# MSVC Windows builds of rustc generate these, which store debugging information
+# Generated by Cargo
+# will have compiled files and executables
+debug/
+target/
+
+# Remove Cargo.lock from gitignore if creating an executable, leave it for libraries
+# More information here https://doc.rust-lang.org/cargo/guide/cargo-toml-vs-cargo-lock.html
+Cargo.lock
+
+# These are backup files generated by rustfmt
+**/*.rs.bk
+
+# MSVC Windows builds of rustc generate these, which store debugging information
 *.pdb

day2/src/main.rs

@@ -14,10 +14,11 @@ fn main() {
         })
         .collect();
 
-    part1(commands)
+    part1(&commands);
+    part2(&commands);
 }
 
-fn part1(commands: Vec<(&str, i32)>) {
+fn part1(commands: &Vec<(&str, i32)>) {
     let mut position = 0;
     let mut depth = 0;
 
@@ -34,3 +35,23 @@ fn part1(commands: Vec<(&str, i32)>) {
     }
     println!("Part 1: {}", position * depth);
 }
+
+fn part2(commands: &Vec<(&str, i32)>) {
+    let mut position = 0;
+    let mut depth = 0;
+    let mut aim = 0;
+
+    for (dir, amt) in commands.iter().map(|a| *a) {
+        let change = match dir {
+            "forward" => (amt, 0),
+            "up" => (0, -amt),
+            "down" => (0, amt),
+            _ => (0, 0),
+        };
+
+        aim += change.1;
+        position += change.0;
+        depth += aim * change.0;
+    }
+    println!("Part 2: {}", position * depth);
+}