days 7-10

day10/src/main.rs

@@ -0,0 +1,83 @@
+use std::collections::VecDeque;
+use std::io::{self, BufRead, Write};
+
+#[derive(Debug)]
+struct Operation {
+    opcode: String,
+    arg: Option<isize>,
+    cycles: usize,
+}
+
+const SIGNAL_TICK_COUNT: usize = 220;
+const DRAW_CRT: usize = 240;
+
+fn main() {
+    let lines = io::stdin().lock().lines().map(|l| l.unwrap());
+
+    let mut program: Vec<Operation> = vec![];
+    let mut queue: VecDeque<&Operation> = VecDeque::new();
+
+    for line in lines {
+        let cmd = line.split(' ').collect::<Vec<&str>>();
+        let op = cmd.first().unwrap();
+        let mut arg: Option<isize> = None;
+
+        if let Some(num) = cmd.get(1) {
+            arg = Some(num.parse::<isize>().unwrap());
+        }
+        let cycles = match op {
+            &"noop" => 1,
+            &"addx" => 2,
+            invalid => panic!("invalid opcode {}", invalid),
+        };
+        program.push(Operation {
+            opcode: op.to_string(),
+            arg,
+            cycles,
+        });
+    }
+
+    // init counters, program and queue
+    let mut x = 1;
+    let mut current_op = program.first().unwrap();
+    let mut cycles_remaining_for_current = current_op.cycles;
+    let mut signal_sum = 0;
+    let mut screen = [[false; 40]; 6];
+
+    for (screen_idx, i) in (1..DRAW_CRT + 1).enumerate() {
+        if cycles_remaining_for_current == 0 {
+            if current_op.opcode == "addx" {
+                x += current_op.arg.unwrap();
+            }
+            current_op = queue.pop_front().unwrap();
+            cycles_remaining_for_current = current_op.cycles;
+        }
+        let cmd = program.get(i % program.len()).unwrap();
+        queue.push_back(cmd);
+        cycles_remaining_for_current -= 1;
+        match i {
+            20 | 60 | 100 | 140 | 180 | 220 => signal_sum += x * i as isize,
+            _ => (),
+        }
+
+        let (scrx, scry): (usize, usize) = (screen_idx / 40, screen_idx % 40);
+        screen[scrx][scry] = x == screen_idx as isize % 40
+            || x - 1 == screen_idx as isize % 40
+            || x + 1 == screen_idx as isize % 40;
+
+        if i == SIGNAL_TICK_COUNT {
+            println!("{}", signal_sum);
+        }
+    }
+    draw_screen(&screen);
+}
+
+fn draw_screen(screen: &[[bool; 40]; 6]) {
+    let mut lock = io::stdout().lock();
+    for y in 0..6 {
+        for x in 0..40 {
+            write!(lock, "{}", if screen[y][x] { "#" } else { "." }).unwrap()
+        }
+        writeln!(lock).unwrap();
+    }
+}