added day 21
This commit is contained in:
Ishan Jain
parent
a6dda67238
commit
50c6a34a28
207
src/day21/1.rs
Normal file
207
src/day21/1.rs
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@ -0,0 +1,207 @@
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#![feature(test)]
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extern crate test;
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use fxhash::FxHashMap;
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use std::collections::VecDeque;
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use rayon::prelude::*;
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use fxhash::FxHashSet;
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const INPUTS: [&str; 2] = [
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"029A
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980A
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179A
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456A
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379A",
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include_str!("./input.txt"),
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];
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const NAV_KEYPAD: [[char; 3]; 4] = [
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['7', '8', '9'],
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['4', '5', '6'],
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['1', '2', '3'],
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[' ', '0', 'A'],
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];
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const DIR_KEYPAD: [[char; 3]; 2] = [
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[' ', '^', 'A'],
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['<', 'v', '>'],
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];
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pub fn run(input: &str) -> i64 {
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let mut seq = input.lines().map(|x| x.chars().collect::<Vec<char>>()).collect::<Vec<Vec<char>>>();
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let mut answer = 0;
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for seq in seq {
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let mut shortest = std::i64::MAX;
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let keypad_path = find_path_on_keypad(&seq);
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let shortest = keypad_path.into_par_iter().map(|keypad_auth| {
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find_path_on_nav(&keypad_auth).into_par_iter().map(|nav1| {
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find_path_on_nav(&nav1).into_iter().map(|x| x.len()).map(|x| x as i64).min().unwrap()
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}).min().unwrap()
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}).min().unwrap();
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let seq = seq.iter().filter(|x| x.is_digit(10)).collect::<String>().parse::<i64>().unwrap();
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answer += seq * shortest;
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}
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answer
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}
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fn find_path_on_nav(seq: &[char]) -> Vec<Vec<char>> {
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let find_coord = |x: char| match x {
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'^' => (0,1),
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'A' => (0,2),
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'<' => (1,0),
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'v' => (1,1),
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'>' => (1,2),
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_ => unreachable!(),
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};
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let mut seq = seq.to_vec();
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seq.insert(0, 'A');
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let seq = seq.iter().map(|&x| find_coord(x)).collect::<Vec<(i64, i64)>>();
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let path = bfs(&seq, (0,0), (2,3), true);
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path
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}
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fn find_path_on_keypad(seq: &[char]) -> Vec<Vec<char>> {
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let find_coord = |x: char| match x {
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'1' => (2,0),
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'2' => (2,1),
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'3' => (2,2),
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'4' => (1,0),
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'5' => (1,1),
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'6' => (1,2),
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'7' => (0,0),
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'8' => (0,1),
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'9' => (0,2),
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'0' => (3,1),
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'A' => (3,2),
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_ => unreachable!(),
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};
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let mut seq = seq.to_vec();
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seq.insert(0, 'A');
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let seq = seq.iter().map(|&x| find_coord(x)).collect::<Vec<(i64, i64)>>();
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let path = bfs(&seq, (3,0), (4,3), false);
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path
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}
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fn bfs(nodes: &[(i64, i64)], ignore: (i64, i64), limits: (i64, i64), shortest_only: bool) -> Vec<Vec<char>> {
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let mut q = VecDeque::new();
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q.push_back((nodes[0], 1, vec![], Bitmap::new()));
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let mut best = vec![];
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let mut out = vec![];
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while let Some(((x, y), mut dest_idx, mut path, mut visited)) = q.pop_front() {
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if !best.is_empty() && ((shortest_only && path.len() >= best.len()) || (!shortest_only && path.len() > best.len())) {
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continue;
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}
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if dest_idx == nodes.len() - 1 && x == nodes[dest_idx].0 && y == nodes[dest_idx].1 {
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path.push('A');
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if best.is_empty() || (!shortest_only && best.len() >= path.len()) || (shortest_only && best.len() > path.len()) {
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best = path.clone();
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out.push(best.clone());
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}
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continue;
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}
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while x == nodes[dest_idx].0 && y == nodes[dest_idx].1 {
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path.push('A');
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visited.clear();
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dest_idx += 1;
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}
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if visited.get(x,y) {
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continue;
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}
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visited.set(x,y);
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for (i,j) in [(0,1), (1,0), (0,-1), (-1,0)].iter() {
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let x = i + x;
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let y = j + y;
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if x < 0 || y < 0 || x >= limits.0 || y >= limits.1 || visited.get(x,y) {
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continue;
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}
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if x == ignore.0 && y == ignore.1 {
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continue;
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}
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let mut path = path.clone();
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match (i,j) {
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(0,1) => path.push('>'),
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(1,0) => path.push('v'),
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(0,-1) => path.push('<'),
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(-1,0) => path.push('^'),
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_ => unreachable!()
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}
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q.push_back(((x,y), dest_idx, path, visited));
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}
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}
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out
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}
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#[derive(Clone,Copy)]
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struct Bitmap {
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inner: u64,
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size: i64,
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}
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impl Bitmap {
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fn new() -> Self {
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Self { inner: 0, size: 5}
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}
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const fn get(&self, x: i64, y: i64) -> bool {
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let offset = (x * self.size + y) as usize;
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(self.inner >> offset & 1) == 1
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}
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fn set(&mut self, x: i64, y: i64) {
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let offset = (x * self.size + y) as usize;
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self.inner |= 1 << offset;
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}
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fn clear(&mut self) {
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self.inner = 0;
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}
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}
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fn main() {
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for input in INPUTS.iter().skip(1) {
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println!("answer = {}", run(input));
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}
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}
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#[bench]
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fn part1(b: &mut test::Bencher) {
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b.iter(|| {
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let v = run(INPUTS[1]);
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test::black_box(v);
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});
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}
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252
src/day21/2.rs
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252
src/day21/2.rs
Normal file
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@ -0,0 +1,252 @@
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#![feature(test)]
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extern crate test;
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use std::sync::LazyLock;
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use std::collections::VecDeque;
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use fxhash::FxHashMap;
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const INPUTS: [&str; 2] = [
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"029A
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980A
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179A
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456A
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379A",
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include_str!("./input.txt"),
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];
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trait KeyPad {
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fn paths(&self) -> &FxHashMap<((i8, i8), (i8, i8)), Vec<Vec<u8>>>;
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fn coord_from_u8(&self, c: u8) -> (i8, i8);
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}
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struct NavKeyPad {
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// grid: [[u8; 3]; 4],
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paths: FxHashMap<((i8, i8), (i8, i8)), Vec<Vec<u8>>>,
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}
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impl KeyPad for LazyLock<NavKeyPad> {
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fn coord_from_u8(&self, c: u8) -> (i8, i8) {
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match c {
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b'1' => (2,0),
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b'2' => (2,1),
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b'3' => (2,2),
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b'4' => (1,0),
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b'5' => (1,1),
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b'6' => (1,2),
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b'7' => (0,0),
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b'8' => (0,1),
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b'9' => (0,2),
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b'0' => (3,1),
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b'A' => (3,2),
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_ => (0,0) // unreachable
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}
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}
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fn paths(&self) -> &FxHashMap<((i8, i8), (i8, i8)), Vec<Vec<u8>>> {
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&self.paths
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}
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}
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const NAV_KEYPAD: LazyLock<NavKeyPad> = LazyLock::new(|| {
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let mut map = FxHashMap::default();
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for a in 0..4 {
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for b in 0..3 {
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for c in 0..4 {
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for d in 0..3 {
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map.insert(((a,b), (c,d)), compute_path((a,b), (c,d), (3,0), (4,3)));
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}
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}
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}
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}
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NavKeyPad {
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//grid: [
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// ['7', '8', '9'],
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// ['4', '5', '6'],
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// ['1', '2', '3'],
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// [' ', '0', 'A'],
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//],
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paths: map,
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}
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});
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struct DirKeyPad{
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// grid: [[u8; 3]; 2],
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paths: FxHashMap<((i8, i8), (i8, i8)), Vec<Vec<u8>>>,
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}
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impl KeyPad for LazyLock<DirKeyPad> {
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fn coord_from_u8(&self, c: u8) -> (i8, i8) {
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match c {
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b'^' => (0,1),
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b'A' => (0,2),
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b'<' => (1,0),
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b'v' => (1,1),
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b'>' => (1,2),
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_ => (0, 0) // unreachable
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}
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}
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fn paths(&self) -> &FxHashMap<((i8, i8), (i8, i8)), Vec<Vec<u8>>> {
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&self.paths
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}
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}
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const DIR_KEYPAD: LazyLock<DirKeyPad> = LazyLock::new(|| {
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let mut map = FxHashMap::default();
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for a in 0..4 {
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for b in 0..3 {
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for c in 0..4 {
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for d in 0..3 {
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map.insert(((a,b), (c,d)), compute_path((a,b), (c,d), (0,0), (2,3)));
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}
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}
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}
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}
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DirKeyPad {
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// grid: [
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// [' ', '^', 'A'],
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// ['<', 'v', '>'],
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// ],
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paths: map,
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}
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});
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fn compute_path((sx,sy): (i8, i8), (ex, ey): (i8, i8), ignore: (i8, i8), limits: (i8, i8)) -> Vec<Vec<u8>> {
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let mut q = VecDeque::new();
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q.push_back((sx,sy, vec![], Bitmap::new()));
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let mut out = vec![];
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while let Some((x, y, path, mut visited)) = q.pop_front() {
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if path.len() > out.last().map(|x: &Vec<u8>| x.len()).unwrap_or(std::usize::MAX) {
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continue;
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}
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if x == ex && y == ey {
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out.push(path);
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continue;
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}
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if visited.get(x,y) {
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continue;
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}
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visited.set(x,y);
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for (i,j) in [(0,1), (1,0), (0,-1), (-1,0)].iter() {
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let x = i + x;
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let y = j + y;
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if x < 0 || y < 0 || x >= limits.0 || y >= limits.1 || visited.get(x, y) {
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continue;
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}
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if x == ignore.0 && y == ignore.1 {
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continue;
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}
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let mut path = path.clone();
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match (i,j) {
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(0,1) => path.push(b'>'),
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(1,0) => path.push(b'v'),
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(0,-1) => path.push(b'<'),
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(-1,0) => path.push(b'^'),
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_ => unreachable!()
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}
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q.push_back((x, y, path, visited));
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}
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}
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out
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}
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pub fn run(input: &str) -> i64 {
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let input = input.as_bytes();
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let seq = input.split(|&x| x == b'\n').map(|x| x.to_vec());
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let mut cache = FxHashMap::default();
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let mut answer = 0;
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for seq in seq {
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let seq_num = seq.iter().filter(|x| x.is_ascii_digit()).fold(0, |a,x| a * 10 + (*x - b'0') as i64);
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let shortest = compute(NAV_KEYPAD, seq, 1 + 25, &mut cache);
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answer += seq_num * shortest;
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}
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answer
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}
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fn compute(
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keypad: impl KeyPad,
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seq: Vec<u8>,
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robots: i8,
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cache: &mut FxHashMap<(i8, usize, Vec<u8>), i64>,
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) -> i64 {
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if robots == 0 {
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return seq.len() as i64;
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}
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if let Some(v) = cache.get(&(robots, seq.len(), seq.clone())) {
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return *v;
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}
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let mut current_pos = keypad.coord_from_u8(b'A');
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let mut smallest_length = 0;
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for &c in seq.iter() {
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let c_pos = keypad.coord_from_u8(c);
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let sequence = keypad.paths().get(&(current_pos, c_pos)).unwrap();
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let mut min = std::i64::MAX;
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for s in sequence {
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let mut s = s.clone();
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s.push(b'A');
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min = std::cmp::min(min, compute(DIR_KEYPAD, s, robots - 1, cache));
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}
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smallest_length += min;
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current_pos = c_pos;
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}
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cache.insert((robots, seq.len(), seq), smallest_length);
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smallest_length
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}
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#[derive(Clone,Copy)]
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struct Bitmap {
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inner: u64,
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size: i8,
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}
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impl Bitmap {
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fn new() -> Self {
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Self { inner: 0, size: 5}
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}
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const fn get(&self, x: i8, y: i8) -> bool {
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let offset = (x * self.size + y) as usize;
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(self.inner >> offset & 1) == 1
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}
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fn set(&mut self, x: i8, y: i8) {
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let offset = (x * self.size + y) as usize;
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self.inner |= 1 << offset;
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}
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}
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fn main() {
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for input in INPUTS.iter() {
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println!("answer = {}", run(input));
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}
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}
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#[bench]
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fn part2(b: &mut test::Bencher) {
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b.iter(|| {
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let v = run(INPUTS[1]);
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test::black_box(v);
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});
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}
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