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|
use crate::prelude::*;
#[derive(Debug, Clone, Copy)]
pub enum Op {
Inp(Register),
Add(Register, Value),
Mul(Register, Value),
Div(Register, Value),
Mod(Register, Value),
Eql(Register, Value),
}
#[derive(Debug, Clone, Copy)]
pub enum Register {
W,
X,
Y,
Z,
}
use Register::*;
impl Register {
fn lvalue<'a>(&self, alu: &'a mut Alu) -> &'a mut i64 {
match self {
W => &mut alu.w,
X => &mut alu.x,
Y => &mut alu.y,
Z => &mut alu.z,
}
}
fn rvalue(&self, alu: &Alu) -> i64 {
match self {
W => alu.w,
X => alu.x,
Y => alu.y,
Z => alu.z,
}
}
}
impl std::str::FromStr for Register {
type Err = anyhow::Error;
fn from_str(s: &str) -> std::result::Result<Self, Self::Err> {
match s {
"w" => Ok(W),
"x" => Ok(X),
"y" => Ok(Y),
"z" => Ok(Z),
_ => Err(anyhow::anyhow!(s.to_string())),
}
}
}
#[derive(Debug, Clone, Copy)]
pub enum Value {
Register(Register),
Number(i64),
}
impl Value {
fn rvalue(&self, alu: &Alu) -> i64 {
match self {
Self::Register(r) => r.rvalue(alu),
Self::Number(n) => *n,
}
}
}
impl std::str::FromStr for Value {
type Err = anyhow::Error;
fn from_str(s: &str) -> std::result::Result<Self, Self::Err> {
match s {
"w" => Ok(Self::Register(W)),
"x" => Ok(Self::Register(X)),
"y" => Ok(Self::Register(Y)),
"z" => Ok(Self::Register(Z)),
_ => Ok(Self::Number(s.parse()?)),
}
}
}
#[derive(Debug)]
pub struct Alu {
w: i64,
x: i64,
y: i64,
z: i64,
}
impl Alu {
fn new() -> Self {
Self {
w: 0,
x: 0,
y: 0,
z: 0,
}
}
fn run(&mut self, ops: impl IntoIterator<Item = Op>, inp: i64) {
self.inp(W, Value::Number(inp));
for op in ops {
match op {
Op::Inp(_) => {
break;
}
Op::Add(a, b) => {
self.add(a, b);
}
Op::Mul(a, b) => {
self.mul(a, b);
}
Op::Div(a, b) => {
self.div(a, b);
}
Op::Mod(a, b) => {
self.modulo(a, b);
}
Op::Eql(a, b) => {
self.eql(a, b);
}
}
}
}
fn inp(&mut self, a: Register, b: Value) {
*a.lvalue(self) = b.rvalue(self)
}
fn add(&mut self, a: Register, b: Value) {
*a.lvalue(self) += b.rvalue(self);
}
fn mul(&mut self, a: Register, b: Value) {
*a.lvalue(self) *= b.rvalue(self);
}
fn div(&mut self, a: Register, b: Value) {
*a.lvalue(self) /= b.rvalue(self);
}
fn modulo(&mut self, a: Register, b: Value) {
*a.lvalue(self) %= b.rvalue(self);
}
fn eql(&mut self, a: Register, b: Value) {
*a.lvalue(self) = i64::from(a.rvalue(self) == b.rvalue(self));
}
}
impl std::fmt::Display for Alu {
fn fmt(
&self,
f: &mut std::fmt::Formatter<'_>,
) -> std::result::Result<(), std::fmt::Error> {
writeln!(f, "Alu {{")?;
writeln!(f, " w: {}", self.w)?;
writeln!(f, " x: {}", self.x)?;
writeln!(f, " y: {}", self.y)?;
writeln!(f, " z: {}", self.z)?;
write!(f, "}}")?;
Ok(())
}
}
fn step(
alu: &mut Alu,
ops: &mut impl Iterator<Item = Op>,
val: &mut i64,
inp: i64,
) -> bool {
if !(1..=9).contains(&inp) {
return false;
}
*val *= 10;
*val += inp;
alu.run(ops, inp);
true
}
fn run(inp: &[i64], ops: &[Op]) -> Option<i64> {
let mut val = 0;
let mut alu = Alu::new();
let mut ops = ops.iter().copied().skip(1);
let mut ops = ops.by_ref();
if !step(&mut alu, &mut ops, &mut val, inp[0]) {
return None;
}
if !step(&mut alu, &mut ops, &mut val, inp[1]) {
return None;
}
if !step(&mut alu, &mut ops, &mut val, inp[2]) {
return None;
}
let z = alu.z;
if !step(&mut alu, &mut ops, &mut val, (z % 26) - 6) {
return None;
}
if !step(&mut alu, &mut ops, &mut val, inp[3]) {
return None;
}
let z = alu.z;
if !step(&mut alu, &mut ops, &mut val, (z % 26) - 4) {
return None;
}
if !step(&mut alu, &mut ops, &mut val, inp[4]) {
return None;
}
if !step(&mut alu, &mut ops, &mut val, inp[5]) {
return None;
}
if !step(&mut alu, &mut ops, &mut val, inp[6]) {
return None;
}
let z = alu.z;
if !step(&mut alu, &mut ops, &mut val, z % 26) {
return None;
}
let z = alu.z;
if !step(&mut alu, &mut ops, &mut val, z % 26) {
return None;
}
let z = alu.z;
if !step(&mut alu, &mut ops, &mut val, (z % 26) - 3) {
return None;
}
let z = alu.z;
if !step(&mut alu, &mut ops, &mut val, (z % 26) - 9) {
return None;
}
let z = alu.z;
if !step(&mut alu, &mut ops, &mut val, (z % 26) - 9) {
return None;
}
if alu.z == 0 {
Some(val)
} else {
None
}
}
pub fn parse(fh: File) -> Result<impl Iterator<Item = Op>> {
Ok(parse::lines(fh).map(|line| {
let captures = regex_captures!(
r"(inp|add|mul|div|mod|eql) ([wxyz])(?: ([wxyz]|-?\d+))?",
&line
)
.unwrap();
match &captures[1] {
"inp" => Op::Inp(captures[2].parse().unwrap()),
"add" => Op::Add(
captures[2].parse().unwrap(),
captures[3].parse().unwrap(),
),
"mul" => Op::Mul(
captures[2].parse().unwrap(),
captures[3].parse().unwrap(),
),
"div" => Op::Div(
captures[2].parse().unwrap(),
captures[3].parse().unwrap(),
),
"mod" => Op::Mod(
captures[2].parse().unwrap(),
captures[3].parse().unwrap(),
),
"eql" => Op::Eql(
captures[2].parse().unwrap(),
captures[3].parse().unwrap(),
),
_ => panic!("unknown opcode: {}", &captures[1]),
}
}))
}
pub fn part1(ops: impl Iterator<Item = Op>) -> Result<i64> {
let ops: Vec<_> = ops.collect();
for d1 in (1..=9).rev() {
for d2 in (1..=9).rev() {
for d3 in (1..=9).rev() {
for d5 in (1..=9).rev() {
for d7 in (1..=9).rev() {
for d8 in (1..=9).rev() {
for d9 in (1..=9).rev() {
let inp = &[d1, d2, d3, d5, d7, d8, d9];
let ret = run(inp, &ops);
if let Some(n) = ret {
return Ok(n);
}
}
}
}
}
}
}
}
panic!("not found");
}
pub fn part2(ops: impl Iterator<Item = Op>) -> Result<i64> {
let ops: Vec<_> = ops.collect();
for d1 in 1..=9 {
for d2 in 1..=9 {
for d3 in 1..=9 {
for d5 in 1..=9 {
for d7 in 1..=9 {
for d8 in 1..=9 {
for d9 in 1..=9 {
let inp = &[d1, d2, d3, d5, d7, d8, d9];
let ret = run(inp, &ops);
if let Some(n) = ret {
return Ok(n);
}
}
}
}
}
}
}
}
panic!("not found");
}
#[test]
fn test() {
assert_eq!(
part1(parse(parse::data(2021, 24).unwrap()).unwrap()).unwrap(),
99299513899971
);
assert_eq!(
part2(parse(parse::data(2021, 24).unwrap()).unwrap()).unwrap(),
93185111127911
);
}
|
