[rs] Simplify 2022_10

rs/src/y2022/d10.rs

@@ -1,39 +1,14 @@
-#[derive(Clone, Copy)]
-struct State {
-    x: i32,
-}
-
-struct Run {
-    history: Vec<State>,
-    now: State,
-}
-
-impl Run {
-    fn new() -> Self {
-        Self {
-            history: vec![],
-            now: State { x: 1 },
-        }
-    }
-
-    fn noop(&mut self) {
-        self.history.push(self.now);
-    }
-
-    fn addx(&mut self, arg: i32) {
-        self.noop();
-        self.noop();
-        self.now.x += arg;
-    }
-}
-
 pub fn solve(input: String) {
-    let mut run = Run::new();
+    let mut history = vec![];
+    let mut reg_x = 1;
+
     for line in input.lines() {
         if line == "noop" {
-            run.noop();
+            history.push(reg_x);
         } else if let Some(arg) = line.strip_prefix("addx ") {
-            run.addx(arg.parse().unwrap());
+            history.push(reg_x);
+            history.push(reg_x);
+            reg_x += arg.parse::<i32>().unwrap();
         } else {
             panic!("Unknown instruction");
         }
@@ -41,18 +16,16 @@ pub fn solve(input: String) {
 
     let part1 = [20, 60, 100, 140, 180, 220]
         .into_iter()
-        .map(|i| run.history[i - 1].x * i as i32)
+        .map(|i| history[i - 1] * i as i32)
         .sum::<i32>();
     println!("Part 1: {part1}");
 
     println!("Part 2:");
-    for chunk in run.history.chunks(40) {
-        for (x, state) in chunk.iter().enumerate() {
-            if (x as i32).abs_diff(state.x) <= 1 {
-                print!("#");
-            } else {
-                print!(".");
-            }
+    for chunk in history.chunks(40) {
+        for (x, reg_x) in chunk.iter().enumerate() {
+            let visible = (x as i32).abs_diff(*reg_x) <= 1;
+            let pixel = if visible { '#' } else { '.' };
+            print!("{pixel}");
         }
         println!();
     }