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use advent_lib::prelude::*;
use std::convert::TryFrom;
fn main() -> Result<()> {
let mut args = std::env::args();
if args.len() != 2 {
eprintln!("Usage: advent input");
}
let _ = args.next();
let filename = args.next().unwrap();
let input = advent_lib::read_lines_file(&filename)?;
let input = advent_lib::group_lines_by_blanks(input);
let mut initial_state: Vec<Vec<bool>> = Vec::new();
for line in &input[0] {
let mut row = Vec::new();
for c in line.chars() {
if c == '#' {
row.push(true);
} else {
row.push(false);
}
}
initial_state.push(row);
}
do_4d(&initial_state, false);
do_4d(&initial_state, true);
Ok(())
}
fn do_4d(initial_state: &Vec<Vec<bool>>, use_w: bool) {
let max_iterations = 6;
let mut hyperspace = init_4d(initial_state, max_iterations, use_w);
for _ in 0 .. max_iterations {
hyperspace = step_4d(&hyperspace, use_w);
}
let active_count = count_active_4d(&hyperspace);
println!("{}", active_count);
}
fn init_4d(initial_state: &Vec<Vec<bool>>, max_iterations: usize, use_w: bool)
-> Vec<Vec<Vec<Vec<bool>>>>
{
let initial_height = initial_state.len();
let initial_width = initial_state[0].len();
let mut hyperspace: Vec<Vec<Vec<Vec<bool>>>> = Vec::new();
for w in 0 .. max_iterations * 2 + 1 {
if w > 0 && !use_w {
continue;
}
let mut space = Vec::new();
for z in 0 .. max_iterations * 2 + 1 {
let mut plane = Vec::new();
for y in 0 .. initial_height + max_iterations * 2 + 1 {
let y_shifted = isize::try_from(y).unwrap()
- isize::try_from(max_iterations).unwrap();
let mut row = Vec::new();
for x in 0 .. initial_width + max_iterations * 2 + 1 {
let x_shifted = isize::try_from(x).unwrap()
- isize::try_from(max_iterations).unwrap();
if ((use_w && w == max_iterations) || (!use_w && w == 0))
&& z == max_iterations
&& y_shifted >= 0 && y_shifted < isize::try_from(initial_height).unwrap()
&& x_shifted >= 0 && x_shifted < isize::try_from(initial_width).unwrap()
{
row.push(initial_state[usize::try_from(y_shifted).unwrap()]
[usize::try_from(x_shifted).unwrap()]);
} else {
row.push(false);
}
}
plane.push(row);
}
space.push(plane);
}
hyperspace.push(space);
}
hyperspace
}
fn step_4d(input_hyperspace: &Vec<Vec<Vec<Vec<bool>>>>, use_w: bool)
-> Vec<Vec<Vec<Vec<bool>>>>
{
let mut output_hyperspace = Vec::new();
for w in 0 .. input_hyperspace.len() {
if w > 0 && !use_w {
continue;
}
let input_space = &input_hyperspace[w];
let mut output_space = Vec::new();
for z in 0 .. input_space.len() {
let input_plane = &input_space[z];
let mut output_plane = Vec::new();
for y in 0 .. input_plane.len() {
let input_row = &input_plane[y];
let mut output_row = Vec::new();
for x in 0 .. input_row.len() {
let mut adjacent_count = 0;
for dw in [-1, 0, 1].iter() {
for dz in [-1, 0, 1].iter() {
for dy in [-1, 0, 1].iter() {
for dx in [-1, 0, 1].iter() {
if *dw == 0 && *dz == 0 && *dy == 0 && *dx == 0 {
continue;
}
let shifted_w = isize::try_from(w).unwrap() + dw;
let shifted_z = isize::try_from(z).unwrap() + dz;
let shifted_y = isize::try_from(y).unwrap() + dy;
let shifted_x = isize::try_from(x).unwrap() + dx;
if shifted_w < 0
|| shifted_w >= isize::try_from(input_hyperspace.len()).unwrap()
{
continue;
}
if shifted_z < 0
|| shifted_z >= isize::try_from(input_space.len()).unwrap()
{
continue;
}
if shifted_y < 0
|| shifted_y >= isize::try_from(input_plane.len()).unwrap()
{
continue;
}
if shifted_x < 0
|| shifted_x >= isize::try_from(input_row.len()).unwrap()
{
continue;
}
if input_hyperspace[usize::try_from(shifted_w).unwrap()]
[usize::try_from(shifted_z).unwrap()]
[usize::try_from(shifted_y).unwrap()]
[usize::try_from(shifted_x).unwrap()]
{
adjacent_count += 1;
}
}
}
}
}
let mut output_cell = false;
if input_row[x] {
if adjacent_count >= 2 && adjacent_count <= 3 {
output_cell = true;
}
} else {
if adjacent_count == 3 {
output_cell = true;
}
}
output_row.push(output_cell);
}
output_plane.push(output_row);
}
output_space.push(output_plane);
}
output_hyperspace.push(output_space);
}
output_hyperspace
}
fn count_active_4d(hyperspace: &Vec<Vec<Vec<Vec<bool>>>>) -> usize {
let mut count = 0;
for space in hyperspace {
for plane in space {
for row in plane {
for cell in row {
if *cell {
count += 1;
}
}
}
}
}
count
}
pub fn debug_4d(hyperspace: &Vec<Vec<Vec<Vec<bool>>>>, use_w: bool) {
let mut output = String::new();
for w in 0 .. hyperspace.len() {
if w > 0 && !use_w {
continue;
}
let space = &hyperspace[w];
for z in 0 .. space.len() {
let plane = &space[z];
if w > 0 || z > 0 {
output.push_str("\n");
}
output.push_str(&format!("w: {}, z: {}\n", w, z));
for row in plane {
for cell in row {
if *cell {
output.push_str("#");
} else {
output.push_str(".");
}
}
output.push_str("\n");
}
}
}
println!("{}", output);
}
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