david/aoc2021
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

Compare commits

base: david:trunk
Branches Tags
david:trunk
..
compare: david:372bc43623d357db04e2058eda5f1c4764228ad1
Branches Tags
david:trunk

No commits in common. "trunk" and "372bc43623d357db04e2058eda5f1c4764228ad1" have entirely different histories.
trunk ... 372bc43623

5 changed files with 16 additions and 350 deletions
Show Stats Expand all files Collapse all files

4
src/day1.rs
View File

@ -1,7 +1,7 @@
use std::collections::VecDeque;
/// Increments count if each sample is larger than the previous.
pub fn part1(input: String) {
pub fn day1_p1(input: String) {
let mut prev = None;
let mut count: u32 = 0;
for line in input.lines() {
@ -22,7 +22,7 @@ pub fn part1(input: String) {
/// 3-sample windowing average (no need to average, just use sum here)
///
/// We need to start comparing when we have all of
pub fn part2(input: String) {
pub fn day1_p2(input: String) {
let mut storage = VecDeque::with_capacity(5);
let mut count = 0;

54
src/day2.rs
View File

@ -1,54 +0,0 @@
struct Position {
pub x: i64,
#[allow(dead_code)]
pub y: i64,
pub z: i64,
}
impl std::default::Default for Position {
fn default() -> Self {
Self { x: 0, y: 0, z: 0 }
}
}
pub fn part1(input: String) {
let mut pos = Position::default();
for line in input.lines() {
let mut command = line.split(' ');
let dir = command.next().unwrap();
let distance = command.next().unwrap().parse::<i64>().unwrap();
match dir {
"forward" => pos.x += distance,
"up" => pos.z += distance,
"down" => pos.z -= distance,
_ => panic!("Invalid input!"),
}
}
println!("{}", pos.x * -pos.z);
}
pub fn part2(input: String) {
let mut pos = Position::default();
let mut attitude = 0i64;
for line in input.lines() {
let mut command = line.split(' ');
let dir = command.next().unwrap();
let distance = command.next().unwrap().parse::<i64>().unwrap();
match dir {
"forward" => {
pos.x += distance;
pos.z += distance * attitude;
}
"up" => attitude += distance,
"down" => attitude -= distance,
_ => panic!("Invalid input!"),
}
}
println!("{}", pos.x * -pos.z);
}

135
src/day3.rs
View File

@ -1,135 +0,0 @@
/// I thought this would be useful for both parts but I was very wrong
fn bit_count(input: &String) -> (Vec<i64>, usize) {
let byte_len = input.lines().next().unwrap().len();
let mut count = vec![0i64; byte_len];
for line in input.lines() {
let mut i = 0;
for c in line.chars() {
if c == '1' {
count[i] += 1;
} else if c == '0' {
count[i] -= 1;
} else {
panic! {"Malformed input!"};
}
i += 1;
}
}
(count, byte_len)
}
/// Returns the product of gamma and epsilon.
///
/// Gamma is determined by the most common bit values at each position in all of the
/// input.
///
/// Epsilon is the inverse, determined by the least common bit values.
pub fn part1(input: String) {
let (count, byte_len) = bit_count(&input);
let mut gamma = 0u64;
let mut epsilon = 0u64;
for i in 0..byte_len {
// ERROR: wrong with even counts
gamma |= ((count[i] > 0) as u64) << (byte_len - (i + 1));
epsilon |= ((count[i] <= 0) as u64) << (byte_len - (i + 1));
}
println!("{}", gamma * epsilon);
}
/// Counts high/low bits in
fn count_bits(data: &Vec<u64>, bit_index: usize, mask: u64, bit_diag: u64) -> (u64, i64) {
let mut bit_prevalance = 0i64;
let mut valid_count = 0u64;
for byte in data {
//println!("byte: {}", bit_diag ^ (byte & mask));
if bit_diag ^ (byte & mask) == 0 {
valid_count += 1;
if (byte & (1 << bit_index)) > 0 {
bit_prevalance += 1;
} else {
bit_prevalance -= 1;
}
}
}
//println!("bit_index: {}, mask: {}, bit_diag: {}, valid_count: {}, bit_prevalance: {}", bit_index, mask, bit_diag, valid_count, bit_prevalance);
(valid_count, bit_prevalance)
}
/// I *could* document this, but why would I want to? :P
/// AOC itself serves as documentation.
pub fn part2(input: String) {
let byte_len = input.lines().next().unwrap().len();
let data: Vec<u64> = input
.lines()
.map(|l| u64::from_str_radix(l, 2).unwrap())
.collect();
let mut generator_mask = 0u64;
let mut generator_diag = 0u64;
let mut generator_value = None;
let mut scrubber_mask = 0u64;
let mut scrubber_diag = 0u64;
let mut scrubber_value = None;
// Diagnostic bit sequence will be different for generator and scrubber
// Logic for counting bits will be the same, just need to keep diagnostic bits seperate
for i in 0..byte_len {
let bit_index = byte_len - i - 1;
// Set diagnostic bit for each piece of data individually
if generator_value.is_none() {
let (valid_count, bit_prevalance) =
count_bits(&data, bit_index, generator_mask, generator_diag);
// We want to match against the most common bit, which is 1 when prevalance is positive.
// We also want to match on one when they are equal.
if bit_prevalance >= 0 {
generator_diag |= 1 << bit_index;
}
generator_mask |= 1 << bit_index;
// Only one valid solution, grab it and get out
if valid_count <= 2 || i == byte_len - 1 {
generator_value = Some(
data.iter()
.filter(|d| generator_diag ^ (*d & generator_mask) == 0)
.next()
.unwrap(),
);
}
}
if scrubber_value.is_none() {
let (valid_count, bit_prevalance) =
count_bits(&data, bit_index, scrubber_mask, scrubber_diag);
// We want to match against the least common bit, which is 1 when prevalance is negative.
// When equal we match against 0.
if bit_prevalance < 0 {
scrubber_diag |= 1 << bit_index;
}
scrubber_mask |= 1 << bit_index;
// Only one valid solution, grab it and get out
if valid_count <= 2 || i == byte_len - 1 {
scrubber_value = Some(
data.iter()
.filter(|d| scrubber_diag ^ (*d & scrubber_mask) == 0)
.next()
.unwrap(),
)
}
}
}
let gen = generator_value.unwrap();
let scrub = scrubber_value.unwrap();
println!("{}", gen * scrub);
}

135
src/day4.rs
View File

@ -1,135 +0,0 @@
use std::convert::TryInto;
struct BingoBoard {
board: [[u8; 5]; 5],
marked: [[bool; 5]; 5],
bingo: bool,
}
impl BingoBoard {
fn new(board: [[u8; 5]; 5]) -> Self {
Self {
board,
marked: [[false; 5]; 5],
bingo: false,
}
}
/// Checks to see if bingo has been achieved.
///
/// Returns true if any row or column is fully marked. (Ignores diagonals)
fn check_bingo(&mut self) -> bool {
// Check rows
for row in self.marked {
if row.iter().all(|marked| *marked) {
self.bingo = true;
return true;
}
}
// Check columns
for i in 0..self.marked.len() {
if self.marked.iter().map(|row| row[i]).all(|marked| marked) {
self.bingo = true;
return true;
}
}
false
}
fn is_bingo(&self) -> bool {
self.bingo
}
/// Checks number for existance on board and marks off any instances of it.
fn check_number(&mut self, number: u8) {
for i in 0..self.board.len() {
for j in 0..self.board[i].len() {
if self.board[i][j] == number {
self.marked[i][j] = true;
}
}
}
}
// Scores board based on input number
fn score(&self, number: u8) -> usize {
let mut score = 0usize;
for i in 0..self.board.len() {
for j in 0..self.board[i].len() {
if !self.marked[i][j] {
score += self.board[i][j] as usize;
}
}
}
score * number as usize
}
}
fn parse_input(input: String) -> (Vec<u8>, Vec<BingoBoard>) {
let mut lines = input.lines();
let input: Vec<u8> = lines
.next()
.unwrap()
.split(',')
.map(|s| str::parse::<u8>(s).unwrap())
.collect();
// Keep building boards until we don't have any more lines to parse
let mut boards = Vec::<BingoBoard>::new();
while let Some(_) = lines.next() {
let mut board = [[0u8; 5]; 5];
for i in 0..board.len() {
let line: Vec<u8> = lines
.next()
.unwrap()
.split_whitespace()
.map(|s| str::parse::<u8>(s).unwrap())
.collect();
board[i] = line.try_into().unwrap();
}
boards.push(BingoBoard::new(board));
}
(input, boards)
}
pub fn part1(input: String) {
let (input, mut boards) = parse_input(input);
for call in input {
// Mark and check boards
// NOTE: making big assumption here that only one board wins
for board in &mut boards {
board.check_number(call);
if board.check_bingo() {
println!("Final score: {}", board.score(call));
return;
}
}
}
}
pub fn part2(input: String) {
let (input, mut boards) = parse_input(input);
let mut final_score = 0usize;
for call in input {
for board in &mut boards {
if !board.is_bingo() {
board.check_number(call);
if board.check_bingo() {
final_score = board.score(call);
}
}
}
}
println!("Last winner's score: {}", final_score);
}

38
src/main.rs
View File

@ -1,9 +1,6 @@
use clap::{App, Arg};
mod day1;
mod day2;
mod day3;
mod day4;
fn main() {
let matches = App::new("AOC 2021 Code")
@ -33,30 +30,23 @@ fn main() {
let part = matches.value_of("part").unwrap_or("1");
let part = str::parse::<u8>(part).expect("Invalid part provided (1 or 2 expected)");
let input = read_input(day).unwrap();
let input = read_input(day, part).unwrap();
// TODO macro-ify
match_days!(1, day1, 2, day2, 3, day3, 4, day4);
match day {
1 => match part {
1 => day1::day1_p1(input),
2 => day1::day1_p2(input),
_ => (),
},
_ => println!("Day {} not completed yet!", day),
}
}
// TODO do the inputs ever change inside of a day?
/// Read inputs into a string
fn read_input(day: u8) -> std::io::Result<String> {
std::fs::read_to_string(format!("inputs/day{}", day))
}
#[macro_export]
macro_rules! match_days {
( $($num:expr, $day:ident),* ) => {
match day {
$(
$num => match part {
1 => $day::part1(input),
2 => $day::part2(input),
_ => println!("Part {} invalid!", part),
},
)*
_ => println!("Day {} not completed yet!", day),
}
};
fn read_input(day: u8, part: u8) -> std::io::Result<String> {
std::fs::read_to_string(format!(
"inputs/day{}p{}",
day, part
))
}