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|
extern crate advent_of_code_2018;
use advent_of_code_2018::*;
use std::error::Error;
use std::path::PathBuf;
use std::collections::{HashMap, HashSet};
// cargo watch -cs "cargo run --release --bin day_16"
struct Instruction {
op: Op,
a: i32,
b: i32,
c: i32
}
impl Instruction {
fn execute(&self, registers: &[i32; 4]) -> [i32; 4] {
use Op::*;
let mut result_registers = registers.clone();
result_registers[self.c as usize] = match self.op {
Addr => registers[self.a as usize] + registers[self.b as usize],
Addi => registers[self.a as usize] + self.b,
Mulr => registers[self.a as usize] * registers[self.b as usize],
Muli => registers[self.a as usize] * self.b,
Banr => registers[self.a as usize] & registers[self.b as usize],
Bani => registers[self.a as usize] & self.b,
Borr => registers[self.a as usize] | registers[self.b as usize],
Bori => registers[self.a as usize] | self.b,
Setr => registers[self.a as usize],
Seti => self.a,
Gtir => if self.a > registers[self.b as usize] { 1 } else { 0 },
Gtri => if registers[self.a as usize] > self.b { 1 } else { 0 },
Gtrr => if registers[self.a as usize] > registers[self.b as usize] { 1 } else { 0 },
Eqir => if self.a == registers[self.b as usize] { 1 } else { 0 },
Eqri => if registers[self.a as usize] == self.b { 1 } else { 0 },
Eqrr => if registers[self.a as usize] == registers[self.b as usize] { 1 } else { 0 }
};
result_registers
}
}
#[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
enum Op {
Addr,
Addi,
Mulr,
Muli,
Banr,
Bani,
Borr,
Bori,
Setr,
Seti,
Gtir,
Gtri,
Gtrr,
Eqir,
Eqri,
Eqrr
}
impl Op {
fn all() -> [Op; 16] {
use Op::*;
[
Addr,
Addi,
Mulr,
Muli,
Banr,
Bani,
Borr,
Bori,
Setr,
Seti,
Gtir,
Gtri,
Gtrr,
Eqir,
Eqri,
Eqrr
]
}
}
struct UnknownInstruction {
before: [i32; 4],
after: [i32; 4],
opcode: i32,
a: i32,
b: i32,
c: i32
}
impl UnknownInstruction {
fn possible_matches(&self) -> HashSet<Op> {
Op::all()
.iter()
.filter(|&&op| {
let instruction = Instruction {
op: op,
a: self.a,
b: self.b,
c: self.c
};
let result = instruction.execute(&self.before);
result == self.after
})
.cloned()
.collect()
}
}
fn main() -> Result<(), Box<Error>> {
let input_part_1 = read_file(&PathBuf::from("inputs/16_1.txt"))?;
let unknown_instructions: Vec<UnknownInstruction> = input_part_1.chunks(3)
.map(|chunk| {
let mut before_iter = chunk[0].trim_matches(|c: char| !c.is_numeric()).split(", ").map(|c| c.parse::<i32>().unwrap());
let before = [
before_iter.next().unwrap(),
before_iter.next().unwrap(),
before_iter.next().unwrap(),
before_iter.next().unwrap(),
];
let mut after_iter = chunk[2].trim_matches(|c: char| !c.is_numeric()).split(", ").map(|c| c.parse::<i32>().unwrap());
let after = [
after_iter.next().unwrap(),
after_iter.next().unwrap(),
after_iter.next().unwrap(),
after_iter.next().unwrap(),
];
let mut instruction_iter = chunk[1].split_whitespace().map(|c| c.parse::<i32>().unwrap());
UnknownInstruction {
before, after,
opcode: instruction_iter.next().unwrap(),
a: instruction_iter.next().unwrap(),
b: instruction_iter.next().unwrap(),
c: instruction_iter.next().unwrap(),
}
})
.collect();
let matches_more_then_3 = unknown_instructions.iter()
.filter(|unknown| {
unknown.possible_matches().len() >= 3
})
.count();
debug!(matches_more_then_3);
let mut opcodes: HashMap<i32, HashSet<Op>> = HashMap::new();
for unknown in unknown_instructions {
let matches = unknown.possible_matches();
let to_insert = match opcodes.get(&unknown.opcode) {
None => matches,
Some(existing) => existing.intersection(&matches).cloned().collect()
};
opcodes.insert(unknown.opcode, to_insert);
}
debug!(opcodes);
let mut known_opcodes: HashMap<i32, Op> = HashMap::new();
while known_opcodes.len() < 16 {
let (opcode, op) = {
let (opcode, opset) = opcodes.iter().find(|(_,set)| set.len() == 1).unwrap();
let op = opset.iter().next().unwrap().clone();
(opcode.clone(), op)
};
known_opcodes.insert(opcode, op);
opcodes.iter_mut().for_each(|(_, set)| {
set.remove(&op);
});
}
debug!(known_opcodes);
let input_part_2 = read_file(&PathBuf::from("inputs/16_2.txt"))?;
let instructions: Vec<Instruction> = input_part_2.iter()
.map(|line| {
let mut instruction_iter = line.split_whitespace().map(|c| c.parse::<i32>().unwrap());
Instruction {
op: known_opcodes.get(&instruction_iter.next().unwrap()).unwrap().clone(),
a: instruction_iter.next().unwrap(),
b: instruction_iter.next().unwrap(),
c: instruction_iter.next().unwrap(),
}
})
.collect();
let mut registers = [0; 4];
for instruction in instructions {
registers = instruction.execute(®isters);
}
debug!(registers);
Ok(())
}
|
