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|
use regex::Regex;
use std::fmt;
#[derive(Clone)]
struct Device {
a: u64,
b: u64,
c: u64,
program: Vec<u8>,
ip: usize,
output: Vec<u8>,
}
impl Device {
fn parse(input: &str) -> Device {
let mut a: u64 = 0;
let mut b: u64 = 0;
let mut c: u64 = 0;
let mut program: Vec<u8> = vec![];
let re = Regex::new(r"Register ([ABC]): ([0-9]+)|Program: ([0-9,]+)").unwrap();
for cap in re.captures_iter(input) {
if let Some(opcodes) = cap.get(3) {
program = opcodes
.as_str()
.split(",")
.map(|op| op.parse().unwrap())
.collect();
continue;
} else {
match &cap[1] {
"A" => a = cap[2].parse().unwrap(),
"B" => b = cap[2].parse().unwrap(),
"C" => c = cap[2].parse().unwrap(),
_ => unreachable!(),
}
}
}
Device {
a,
b,
c,
program,
ip: 0,
output: vec![],
}
}
fn instruction(&self) -> Option<(Instruction, u8)> {
if self.ip < self.program.len() {
Some((self.program[self.ip].into(), self.program[self.ip + 1]))
} else {
None
}
}
fn read_next_instruction(&mut self) -> Option<(Instruction, u8)> {
let res = self.instruction();
if res.is_some() {
self.ip += 2;
}
res
}
fn get_combo(&self, op: u8) -> u64 {
match op {
0..=3 => op as u64,
4 => self.a,
5 => self.b,
6 => self.c,
_ => unimplemented!(),
}
}
fn output(&self) -> String {
self.output
.iter()
.map(|n| format!("{}", n))
.collect::<Vec<_>>()
.join(",")
}
fn step(&mut self) -> bool {
// println!("{}", self);
let Some((instruction, operand)) = self.read_next_instruction() else {
return false;
};
match instruction {
Adv => self.a /= 2u64.pow(self.get_combo(operand) as u32),
Bxl => self.b ^= operand as u64,
Bst => self.b = self.get_combo(operand) % 8,
Jnz => {
if self.a != 0 {
self.ip = operand as usize;
}
}
Bxc => self.b ^= self.c,
Out => self.output.push((self.get_combo(operand) % 8) as u8),
Bdv => self.b = self.a / 2u64.pow(self.get_combo(operand) as u32),
Cdv => self.c = self.a / 2u64.pow(self.get_combo(operand) as u32),
};
true
}
fn run(&mut self) -> String {
while self.step() {}
self.output()
}
}
#[derive(Debug)]
enum Instruction {
Adv,
Bxl,
Bst,
Jnz,
Bxc,
Out,
Bdv,
Cdv,
}
use Instruction::*;
impl From<u8> for Instruction {
fn from(item: u8) -> Instruction {
match item {
0 => Adv,
1 => Bxl,
2 => Bst,
3 => Jnz,
4 => Bxc,
5 => Out,
6 => Bdv,
7 => Cdv,
_ => panic!(),
}
}
}
impl fmt::Display for Device {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
writeln!(f, "Registers: A={} B={} C={}", self.a, self.b, self.c)?;
writeln!(f, "{:?}", self.program)?;
let spaces = 1 + 3 * self.ip;
let curri = match self.instruction() {
Some((i, op)) => {
let combo = self.get_combo(op);
if op < 4 {
format!(" {i:?}({op})")
} else {
format!(" {i:?}({op}) (combo: {combo})")
}
}
None => "".to_string(),
};
writeln!(
f,
"{}^{}",
(0..spaces).map(|_| " ").collect::<String>(),
curri
)?;
writeln!(f, "Output: {:?}", self.output())
}
}
fn p1(input: &str) -> String {
let mut dev = Device::parse(input);
let result = dev.run();
result.to_string()
}
fn p2(_input: &str) -> String {
let result = "TODO";
result.to_string()
}
fn main() {
aoc2024::run_day("17", p1, p2);
}
|
