From 274266a31829e86512f9ce5edc818e1381511236 Mon Sep 17 00:00:00 2001
From: Justin Wernick <j.wernick@eyeo.com>
Date: Sat, 10 Dec 2022 11:52:15 +0200
Subject: Day 10

---
 2022/src/bin/day_10.rs | 103 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 103 insertions(+)
 create mode 100644 2022/src/bin/day_10.rs

(limited to '2022/src/bin')

diff --git a/2022/src/bin/day_10.rs b/2022/src/bin/day_10.rs
new file mode 100644
index 0000000..6999c52
--- /dev/null
+++ b/2022/src/bin/day_10.rs
@@ -0,0 +1,103 @@
+use nom::{
+    bytes::complete::tag,
+    character::complete::{i32, line_ending},
+    combinator::map,
+    multi::{many0, separated_list1},
+    sequence::{pair, tuple},
+    IResult,
+};
+use std::fs;
+
+fn main() -> Result<(), Box<dyn std::error::Error>> {
+    let input = fs::read_to_string("inputs/day_10.txt")?;
+    let program = Program::parser(&input).unwrap().1;
+    let result = program.process();
+
+    dbg!(result.sum_of_signal_strengths(&[20, 60, 100, 140, 180, 220]));
+
+    for y in 0..6 {
+        for x in 0..40 {
+            if result.pixel_should_activate(x, y) {
+                print!("#");
+            } else {
+                print!(".");
+            }
+        }
+        println!();
+    }
+    Ok(())
+}
+
+#[derive(Debug)]
+struct Program(Vec<TimeSequence>);
+
+#[derive(Debug, Default)]
+struct ProgramResult(Vec<TimeSequence>);
+
+#[derive(Debug, Clone)]
+struct TimeSequence {
+    time: u32,
+    value: i32,
+}
+
+impl Program {
+    fn parser(input: &str) -> IResult<&str, Self> {
+        map(separated_list1(line_ending, TimeSequence::parser), Program)(input)
+    }
+
+    fn process(&self) -> ProgramResult {
+        let mut result = ProgramResult::default();
+
+        let mut current_state = TimeSequence { time: 1, value: 1 };
+        result.0.push(current_state.clone());
+
+        for next_step in &self.0 {
+            current_state.time += next_step.time;
+            current_state.value += next_step.value;
+            result.0.push(current_state.clone());
+        }
+
+        result
+    }
+}
+
+impl TimeSequence {
+    fn parser(input: &str) -> IResult<&str, Self> {
+        map(
+            tuple((many0(pair(tag("noop"), line_ending)), tag("addx "), i32)),
+            |(noops, _, value)| TimeSequence {
+                time: noops.len() as u32 + 2,
+                value,
+            },
+        )(input)
+    }
+}
+
+impl ProgramResult {
+    fn value_at(&self, time: u32) -> i32 {
+        self.0
+            .iter()
+            .filter(|t| t.time <= time)
+            .map(|t| t.value)
+            .last()
+            .unwrap_or(0)
+    }
+
+    fn signal_strength_at(&self, time: u32) -> i32 {
+        let value = self.value_at(time);
+        value * time as i32
+    }
+
+    fn sum_of_signal_strengths(&self, times: &[u32]) -> i32 {
+        times
+            .iter()
+            .map(|time| self.signal_strength_at(*time))
+            .sum()
+    }
+
+    fn pixel_should_activate(&self, x: usize, y: usize) -> bool {
+        let time = (y * 40 + x + 1) as u32;
+        let sprite_middle = self.value_at(time);
+        ((x as i32) - sprite_middle).abs() <= 1
+    }
+}
-- 
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