use std::io; use std::io::BufRead; #[derive(Debug)] enum Operation { Add { x: i32, y: i32, addr: usize }, Multiply { x: i32, y: i32, addr: usize }, Input { value: i32, addr: usize }, Output { value: i32 }, JumpIfTrue { value: i32, addr: i32 }, JumpIfFalse { value: i32, addr: i32 }, LessThan { first: i32, second: i32, addr: i32 }, Equals { first: i32, second: i32, addr: i32 }, } #[derive(Debug)] enum Mode { Immediate, Position, } enum ParameterPosition { First, Second, } impl Into for ParameterPosition { fn into(self) -> usize { match self { ParameterPosition::First => 2, ParameterPosition::Second => 3, } } } impl Into for &char { fn into(self) -> Mode { match self { '0' => Mode::Position, '1' => Mode::Immediate, _ => unreachable!(), } } } fn get_next(input: &[i32], pos: &mut i32, mode: Mode) -> i32 { let value = input[*pos as usize]; let next = match mode { Mode::Position => input[value as usize], Mode::Immediate => value, }; *pos += 1; next } fn get_mode(raw_opcode: &[char], pos: ParameterPosition) -> Mode { raw_opcode.get::(pos.into()).unwrap_or(&'0').into() } fn next_operation(input: &[i32], pos: &mut i32, inp: i32) -> Option { let next = get_next(input, pos, Mode::Immediate); let mut raw_opcode: Vec<_> = next.to_string().chars().collect(); raw_opcode.reverse(); match raw_opcode[0] { '1' => Some(Operation::Add { x: get_next(input, pos, get_mode(&raw_opcode, ParameterPosition::First)), y: get_next(input, pos, get_mode(&raw_opcode, ParameterPosition::Second)), addr: get_next(input, pos, Mode::Immediate) as usize, }), '2' => Some(Operation::Multiply { x: get_next(input, pos, get_mode(&raw_opcode, ParameterPosition::First)), y: get_next(input, pos, get_mode(&raw_opcode, ParameterPosition::Second)), addr: get_next(input, pos, Mode::Immediate) as usize, }), '3' => Some(Operation::Input { value: inp, addr: get_next(input, pos, Mode::Immediate) as usize, }), '4' => Some(Operation::Output { value: get_next(input, pos, get_mode(&raw_opcode, ParameterPosition::First)), }), '5' => Some(Operation::JumpIfTrue { value: get_next(input, pos, get_mode(&raw_opcode, ParameterPosition::First)), addr: get_next(input, pos, get_mode(&raw_opcode, ParameterPosition::Second)), }), '6' => Some(Operation::JumpIfFalse { value: get_next(input, pos, get_mode(&raw_opcode, ParameterPosition::First)), addr: get_next(input, pos, get_mode(&raw_opcode, ParameterPosition::Second)), }), '7' => Some(Operation::LessThan { first: get_next(input, pos, get_mode(&raw_opcode, ParameterPosition::First)), second: get_next(input, pos, get_mode(&raw_opcode, ParameterPosition::Second)), addr: get_next(input, pos, Mode::Immediate), }), '8' => Some(Operation::Equals { first: get_next(input, pos, get_mode(&raw_opcode, ParameterPosition::First)), second: get_next(input, pos, get_mode(&raw_opcode, ParameterPosition::Second)), addr: get_next(input, pos, Mode::Immediate), }), '9' => None, _ => unreachable!(), } } fn execute(op: Operation, input: &mut Vec, pos: &mut i32) { match op { Operation::Add { x, y, addr } => input[addr as usize] = x + y, Operation::Multiply { x, y, addr } => input[addr as usize] = x * y, Operation::Input { value, addr } => input[addr] = value, Operation::Output { value } => { if value != 0 { println!("{}", value) } } Operation::JumpIfTrue { value, addr } => { if value != 0 { *pos = addr } } Operation::JumpIfFalse { value, addr } => { if value == 0 { *pos = addr } } Operation::LessThan { first, second, addr, } => input[addr as usize] = (first < second) as i32, Operation::Equals { first, second, addr, } => input[addr as usize] = (first == second) as i32, } } pub fn main() { let mut input: Vec = io::stdin() .lock() .lines() .next() .unwrap() .unwrap() .split(',') .map(|n| n.parse().unwrap()) .collect(); let mut pos = 0; let mut part2_input = input.clone(); println!("Part 1:"); while let Some(op) = next_operation(&input, &mut pos, 1) { execute(op, &mut input, &mut pos); } pos = 0; println!("Part 2:"); while let Some(op) = next_operation(&part2_input, &mut pos, 5) { execute(op, &mut part2_input, &mut pos); } }