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extern crate structopt;
#[macro_use]
extern crate structopt_derive;
use structopt::StructOpt;
use std::path::PathBuf;
use std::io::BufReader;
use std::io::prelude::*;
use std::fs::File;
use std::process;
#[derive(StructOpt, Debug)]
#[structopt(name = "AOC2017", about = "An Advent of Code CLI arguments object.")]
struct AdventCli {
#[structopt(help = "Which part of the puzzle you are solving")]
part: u32,
#[structopt(help = "Input file", parse(from_os_str))]
input: PathBuf
}
pub struct AdventArgs {
pub part: u32,
pub input: Vec<String>
}
impl AdventArgs {
pub fn init() -> AdventArgs {
let opt = AdventCli::from_args();
let input = match AdventArgs::read_file(&opt.input) {
Ok(input) => input,
Err(error) => {
// Typically I would think of exiting the program like
// this to be bad form, but in this case I'm matching the
// interface of StructOpt: if the input parameters were
// invalid, just quit now with a nice message.
eprintln!("Error reading file: {}", error);
process::exit(1);
}
};
AdventArgs {
part: opt.part,
input: input
}
}
fn read_file(file: &PathBuf) -> Result<Vec<String>, std::io::Error> {
let file = File::open(file)?;
let file_reader = BufReader::new(file);
file_reader.lines()
.collect::<Result<Vec<_>, _>>()
.map(AdventArgs::preprocess_file_lines)
}
fn preprocess_file_lines(lines: Vec<String>) -> Vec<String> {
lines.iter()
.filter(|line| line.len() > 0)
.map(|line| line.trim_right().to_string())
.collect()
}
pub fn one_number_input(&self) -> Result<i32, std::num::ParseIntError> {
self.input[0].parse()
}
pub fn number_per_line_input(&self) -> Result<Vec<i32>, std::num::ParseIntError> {
self.input.iter().map(|line| line.parse()).collect()
}
}
pub fn parse_space_separated_ints(line: &String) -> Result<Vec<i32>, std::num::ParseIntError> {
line.split_whitespace()
.map(|x| x.parse::<i32>())
.collect()
}
#[derive(Hash, Eq, PartialEq, Debug, Clone, Copy)]
pub struct Point {
pub x: i32,
pub y: i32
}
impl Point {
pub fn up(&self) -> Point {
Point {
y: self.y-1,
..*self
}
}
pub fn down(&self) -> Point {
Point {
y: self.y+1,
..*self
}
}
pub fn left(&self) -> Point {
Point {
x: self.x-1,
..*self
}
}
pub fn right(&self) -> Point {
Point {
x: self.x+1,
..*self
}
}
pub fn shift(&self, dir: &Direction) -> Point {
use Direction::*;
match *dir {
Right => self.right(),
Left => self.left(),
Up => self.up(),
Down => self.down()
}
}
}
#[derive(Debug)]
pub enum Direction {
Left,
Up,
Down,
Right
}
impl Direction {
pub fn rotate_left(&self) -> Direction {
use Direction::*;
match *self {
Right => Up,
Up => Left,
Left => Down,
Down => Right
}
}
pub fn rotate_right(&self) -> Direction {
use Direction::*;
match *self {
Right => Down,
Up => Right,
Left => Up,
Down => Left
}
}
}
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub struct Point3d {
pub x: i32,
pub y: i32,
pub z: i32
}
impl std::ops::Add for Point3d {
type Output = Point3d;
fn add(self, other: Point3d) -> Point3d {
Point3d {
x: self.x + other.x,
y: self.y + other.y,
z: self.z + other.z
}
}
}
impl Point3d {
pub fn manhattan_distance(&self) -> i32 {
self.x.abs() + self.y.abs() + self.z.abs()
}
}
pub fn knot_hash(input: &String) -> String {
let suffix: [usize; 5] = [17, 31, 73, 47, 23];
let lengths: Vec<usize> = input.as_bytes()
.iter().map(|&x| x as usize)
.chain(suffix.iter().cloned())
.collect();
let mut position = 0;
let mut list: Vec<u32> = (0..256).collect();
for i in 0..64 {
let skip = lengths.len() * i;
knot_hash_round(&mut list, &lengths, &mut position, skip);
}
let mut current_char = 0;
let mut result = String::new();
for (i, l) in list.iter().enumerate() {
current_char = current_char ^ l;
if i % 16 == 15 {
result.push_str(&format!("{:02x}", current_char));
current_char = 0;
}
}
result
}
fn knot_hash_round(list: &mut Vec<u32>, lengths: &Vec<usize>, position: &mut usize, skip: usize) {
for (inner_skip, &length) in lengths.iter().enumerate() {
knot_hash_reverse_segment(list, *position, length);
*position = (*position + length + skip + inner_skip) % list.len();
}
}
fn knot_hash_reverse_segment(list: &mut Vec<u32>, position: usize, length: usize) {
let mut a = position;
let mut b = position + length - 1;
let len = list.len();
while a < b {
list.swap(a%len, b%len);
a += 1;
b -= 1;
}
}
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