Day 8 rust

This commit is contained in:
Sijmen 2020-12-08 20:31:12 +01:00
parent 4793f79e79
commit c7af8e833b
Signed by: vijfhoek
GPG Key ID: DAF7821E067D9C48
1 changed files with 130 additions and 3 deletions

View File

@ -263,8 +263,131 @@ mod day05 {
} }
} }
mod day06 {
use std::time::Duration;
pub fn run(_: bool) -> Duration {
Duration::new(0, 0)
}
}
mod day07 {
use std::time::Duration;
pub fn run(_: bool) -> Duration {
Duration::new(0, 0)
}
}
mod day08 {
use std::{
collections::HashSet,
time::{Duration, Instant},
};
#[derive(Debug, Copy, Clone)]
enum Instruction {
Acc(i32),
Jmp(i32),
Nop,
}
fn part1(instructions: &[Instruction]) -> (i32, Vec<i32>) {
let mut accumulator = 0;
let mut pc = 0;
let mut pc_history = HashSet::new();
let mut jumps = Vec::new();
loop {
match instructions[pc as usize] {
Instruction::Acc(i) => accumulator += i,
Instruction::Jmp(i) => {
let target = pc + i - 1;
if !pc_history.insert(target) {
break (accumulator, jumps);
}
jumps.push(pc);
pc += i - 1
}
Instruction::Nop => (),
};
pc += 1;
}
}
fn part2(instructions: &[Instruction], skip: i32) -> Option<i32> {
let mut accumulator = 0;
let mut pc = 0;
let mut pc_history = HashSet::new();
loop {
if pc != skip {
match instructions.get(pc as usize) {
Some(Instruction::Acc(i)) => accumulator += i,
Some(Instruction::Jmp(i)) => {
let target = pc + i;
if !pc_history.insert(target) {
break None;
}
pc = target - 1;
}
Some(Instruction::Nop) => (),
None => break Some(accumulator),
};
}
pc += 1;
}
}
pub fn run(print: bool) -> Duration {
let input = std::fs::read_to_string("inputs/day08").unwrap();
let instant = Instant::now();
let instructions: Vec<_> = input
.lines()
.map(|line| {
let operation = &line[0..3];
let value: i32 = line[4..].parse().unwrap();
match operation {
"acc" => Instruction::Acc(value),
"jmp" => Instruction::Jmp(value),
"nop" => Instruction::Nop,
_ => unreachable!(operation),
}
})
.collect();
let (part1, jumps) = part1(&instructions);
let part2 = jumps
.iter()
.rev()
.find_map(|skip_pc| part2(&instructions, *skip_pc))
.unwrap();
let elapsed = instant.elapsed();
if print {
dbg!(elapsed, part1, part2);
}
elapsed
}
}
fn main() { fn main() {
let days = [day01::run, day02::run, day03::run, day04::run, day05::run]; let days = [
day01::run,
day02::run,
day03::run,
day04::run,
day05::run,
day06::run,
day07::run,
day08::run,
];
if let Some(day) = std::env::args().nth(1) { if let Some(day) = std::env::args().nth(1) {
let day: usize = day.parse().expect("day not an integer"); let day: usize = day.parse().expect("day not an integer");
@ -276,11 +399,15 @@ fn main() {
let mut total = Duration::new(0, 0); let mut total = Duration::new(0, 0);
for day in 0..days.len() { for day in 0..days.len() {
let mut elapsed = Duration::new(0, 0);
for _ in 0..repetitions { for _ in 0..repetitions {
total += days[day](false) / repetitions; elapsed += days[day](false) / repetitions;
} }
println!("Day {:>2}: {:?}", day + 1, elapsed);
total += elapsed;
} }
dbg!(total); println!("-------------------");
println!("Total: {:?}", total);
} }
} }