parent
47fb1fcdd8
commit
f777a09f63
@ -0,0 +1,10 @@ |
||||
[package] |
||||
name = "day11" |
||||
version = "0.1.0" |
||||
authors = ["inga-lovinde <52715130+inga-lovinde@users.noreply.github.com>"] |
||||
edition = "2018" |
||||
|
||||
# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html |
||||
|
||||
[dependencies] |
||||
ndarray = "0.14.0" |
@ -0,0 +1,193 @@ |
||||
#![feature(trait_alias)] |
||||
|
||||
use std::io::{self, BufRead}; |
||||
use ndarray::Array2; |
||||
|
||||
// state (u32 for simplicity reasons): 0/1/2/3 (in this case, 1 = floor, 2 = seat free, 3 = seat taken)
|
||||
|
||||
// every cell is u32, where:
|
||||
// * lowest 16 bits describe its neighbours:
|
||||
// * bits 0-1 (cell & 3) is the state of upper left neighbour,
|
||||
// * bits 2-3 ((cell >> 2) & 3) is the state of upper neighbour,
|
||||
// * bits 4-5 is the state of upper right neighbour,
|
||||
// * bits 6-7, left,
|
||||
// * bits 8-9, right,
|
||||
// * bits 10-11, bottom left,
|
||||
// * bits 12-13, bottom,
|
||||
// * bits 14-15, bottom right
|
||||
// * bits 16-17 ((cell >> 16) & 3) describe the cell itself
|
||||
|
||||
// rule: cell (u32, 18 bits used) -> new cell (u32)
|
||||
|
||||
// board is indexed by [row, column],
|
||||
// where row is from top to bottom and column is from left to right
|
||||
|
||||
trait StateRules = Fn([usize; 4], u32) -> u32; |
||||
|
||||
struct Game { |
||||
cell_rules: Vec<u32>, |
||||
board: Array2<u32>, |
||||
rows: usize, |
||||
columns: usize, |
||||
} |
||||
|
||||
impl Game { |
||||
// only updates the state of this cell for it and its neighbours;
|
||||
// only state of this cell is used from new_cell
|
||||
fn update_cell(&mut self, row: usize, column: usize, new_cell: u32) { |
||||
let state_diff = (new_cell ^ self.board[[row, column]]) >> 16; |
||||
|
||||
self.board[[row, column]] ^= state_diff << 16; |
||||
|
||||
self.board[[row+1, column+1]] ^= state_diff; |
||||
self.board[[row+1, column ]] ^= state_diff << 2; |
||||
self.board[[row+1, column-1]] ^= state_diff << 4; |
||||
self.board[[row , column+1]] ^= state_diff << 6; |
||||
self.board[[row , column-1]] ^= state_diff << 8; |
||||
self.board[[row-1, column+1]] ^= state_diff << 10; |
||||
self.board[[row-1, column ]] ^= state_diff << 12; |
||||
self.board[[row-1, column-1]] ^= state_diff << 14; |
||||
} |
||||
|
||||
fn build_cell_rules<T: StateRules>(state_rules: T) -> Vec<u32> { |
||||
let mut result = vec![0u32; 1 << 18]; |
||||
|
||||
for i in 0..1usize << 18 { |
||||
let cell = i as u32; |
||||
let current_state = (cell >> 16) & 3; |
||||
let mut state_counts = [0usize; 4]; |
||||
for j in 0..8 { |
||||
state_counts[((cell >> (2*j)) & 3) as usize] += 1; |
||||
} |
||||
|
||||
let new_state = state_rules(state_counts, current_state); |
||||
let new_cell = cell ^ ((current_state ^ new_state) << 16); |
||||
result[i] = new_cell; |
||||
} |
||||
|
||||
result |
||||
} |
||||
|
||||
pub fn next_step(&mut self) -> usize { |
||||
let mut changes: Vec<_> = vec![]; |
||||
for row in 1..self.rows-1 { |
||||
for column in 1..self.columns-1 { |
||||
let old_cell = self.board[[row, column]]; |
||||
let new_cell = self.cell_rules[old_cell as usize]; |
||||
if new_cell != old_cell { |
||||
changes.push((row, column, new_cell)); |
||||
} |
||||
} |
||||
} |
||||
|
||||
let changes_count = changes.len(); |
||||
for (row, column, new_cell) in changes { |
||||
self.update_cell(row, column, new_cell); |
||||
} |
||||
|
||||
changes_count |
||||
} |
||||
|
||||
pub fn from_input<T: StateRules>(input_data: &[String], state_rules: T) -> Game { |
||||
let rows = input_data.len() + 2; |
||||
let columns = input_data[0].len() + 2; |
||||
let mut states = Array2::zeros((rows, columns)); |
||||
|
||||
for row in 1..rows-1 { |
||||
let chars = input_data[row-1].chars().collect::<Vec<_>>(); |
||||
for column in 1..columns-1 { |
||||
let ch = chars[column-1]; |
||||
states[[row, column]] = match ch { |
||||
'.' => 1, |
||||
'L' => 2, |
||||
'#' => 3, |
||||
_ => 0, |
||||
} |
||||
} |
||||
} |
||||
|
||||
let mut board = Array2::zeros((rows, columns)); |
||||
|
||||
/* |
||||
board[[0, 0]] = states[[1, 1]] << 14; |
||||
board[[0, columns-1]] = states[[1, columns-2]] << 10; |
||||
board[[rows-1, 0]] = states[[rows-2, 1]] << 4; |
||||
board[[rows-1, columns-1]] = states[[rows-2, columns-2]]; |
||||
|
||||
for row in 1..rows-1 { |
||||
board[[row, 0]] = (states[[row-1, 1]] << 4) ^ (states[[row, 1]] << 8) ^ (states[[row+1, 1]] << 14); |
||||
board[[row, columns-1]] = (states[[row-1, columns-2]]) ^ (states[[row, columns-2]] << 6) ^ (states[[row+1, columns-2]] << 10); |
||||
} |
||||
|
||||
for column in 1..columns-1 { |
||||
board[[0, column]] = (states[[1, column-1]] << 10) ^ (states[[1, column]] << 12) ^ (states[[1, column+1]] << 14); |
||||
board[[rows-1, column]] = (states[[rows-2, column-1]]) ^ (states[[rows-2, column]] << 2) ^ (states[[rows-2, column+1]] << 4); |
||||
} |
||||
*/ |
||||
|
||||
for row in 1..rows-1 { |
||||
for column in 1..columns-1 { |
||||
board[[row, column]] = |
||||
(states[[row-1, column-1]] ) ^ |
||||
(states[[row-1, column ]] << 2) ^ |
||||
(states[[row-1, column+1]] << 4) ^ |
||||
(states[[row , column-1]] << 6) ^ |
||||
(states[[row , column+1]] << 8) ^ |
||||
(states[[row+1, column-1]] << 10) ^ |
||||
(states[[row+1, column ]] << 12) ^ |
||||
(states[[row+1, column+1]] << 14) ^ |
||||
(states[[row, column]] << 16); |
||||
} |
||||
} |
||||
|
||||
let cell_rules = Self::build_cell_rules(state_rules); |
||||
|
||||
Game { |
||||
rows, |
||||
columns, |
||||
board, |
||||
cell_rules, |
||||
} |
||||
} |
||||
|
||||
pub fn print_board(&self) { |
||||
for row in (&self.board).genrows() { |
||||
println!("{}", row.iter().map(|state| { |
||||
match (state >> 16) & 3 { |
||||
1 => '.', |
||||
2 => 'L', |
||||
3 => '#', |
||||
_ => '0', |
||||
} |
||||
}).collect::<String>()); |
||||
} |
||||
} |
||||
|
||||
pub fn get_count_of_cells_for_state(&self, state: u32) -> usize { |
||||
(&self.board).iter().filter(|&&cell| ((cell >> 16) & 3) == state).count() |
||||
} |
||||
} |
||||
|
||||
fn main() { |
||||
let stdin = io::stdin(); |
||||
let lines: Vec<_> = stdin.lock().lines().map(|line| line.unwrap()).collect(); |
||||
let mut game = Game::from_input(&lines, |state_counts: [usize; 4], current_state| { |
||||
match current_state { |
||||
2 => if state_counts[3] == 0 { 3 } else { 2 }, |
||||
3 => if state_counts[3] >= 4 { 2 } else { 3 }, |
||||
other => other |
||||
} |
||||
}); |
||||
|
||||
for i in 1.. { |
||||
let changes_count = game.next_step(); |
||||
println!("Iteration {}; changed cells: {}", i, changes_count); |
||||
if changes_count == 0 { |
||||
break; |
||||
} |
||||
} |
||||
|
||||
println!("Board stabilized at {} occupied seats", game.get_count_of_cells_for_state(3)); |
||||
game.print_board(); |
||||
println!("Board stabilized at {} occupied seats", game.get_count_of_cells_for_state(3)); |
||||
} |
Loading…
Reference in new issue