feat: solve day 2 part 2

src/day2.rs

@@ -53,6 +53,23 @@ pub fn part1(commands: &[CommandLine]) -> u32 {
     return depth * horizontal;
 }
 
+pub fn part2(commands: &[CommandLine]) -> u32 {
+    let mut depth = 0;
+    let mut horizontal = 0;
+    let mut aim = 0;
+    for command in commands {
+        match command.0 {
+            Command::Up      => aim -= command.1,
+            Command::Down    => aim += command.1,
+            Command::Forward => {
+                horizontal += command.1;
+                    depth += aim * command.1;
+            }
+        }
+    }
+    return depth * horizontal;
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -70,5 +87,19 @@ mod tests {
         let result = part1(&commands);
         assert_eq!(result, 150);
     }
+
+    #[test]
+    fn part2_example() {
+        let commands = [
+            CommandLine(Command::Forward, 5),
+            CommandLine(Command::Down, 5),
+            CommandLine(Command::Forward, 8),
+            CommandLine(Command::Up, 3),
+            CommandLine(Command::Down, 8),
+            CommandLine(Command::Forward, 2)
+        ];
+        let result = part2(&commands);
+        assert_eq!(result, 900)
+    }
 }
 

src/main.rs

@@ -10,9 +10,9 @@ fn main() {
     // let result2 = day1::part2(&input);
     
     let result1 = day2::part1(&input);
-    // let result2 = day2::part2(&input);
+    let result2 = day2::part2(&input);
 
     println!("Part 1 result: {}", result1);
-    // println!("Part 2 result: {}", result2);
+    println!("Part 2 result: {}", result2);
 }