advent-of-code/2019/05/src/main.rs

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