Split lib from main

This commit is contained in:
Timothy Warren 2022-12-23 11:25:21 -05:00
parent 5c8f3fc2ab
commit 2c5e910b88
3 changed files with 291 additions and 282 deletions

287
day12/src/lib.rs Normal file
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@ -0,0 +1,287 @@
mod node;
use core::fmt;
use node::Node;
use aoc_shared::enums::Direction;
use aoc_shared::grid::Grid as BaseGrid;
use aoc_shared::impl_grid_newtype;
#[derive(Debug, Copy, Clone, PartialEq)]
enum CellType {
Start,
End,
Waypoint(u8),
}
#[derive(Debug, Clone)]
struct Cell {
kind: CellType,
idx: usize,
coord: (usize, usize),
}
impl Cell {
pub fn new(kind: CellType, idx: usize, coord: (usize, usize)) -> Self {
Cell { kind, idx, coord }
}
pub fn get_height(&self) -> u8 {
match self.kind {
CellType::Start => 0,
CellType::End => 25,
CellType::Waypoint(c) => c,
}
}
}
// ----------------------------------------------------------------------------
pub struct Grid<T>(BaseGrid<T>);
impl_grid_newtype!(Grid, BaseGrid<Cell>, Cell);
impl Grid<Cell> {
pub fn from_file_str(file_str: &str) -> Self {
let first_line = file_str.lines().next().unwrap();
let width = first_line.len();
let mut grid = Grid::new(width);
let mut idx = 0usize;
for c in file_str.chars() {
let kind = match c {
'S' => CellType::Start,
'E' => CellType::End,
'a'..='z' => CellType::Waypoint(c as u8 - b'a'),
'\r' | '\n' => continue,
_ => panic!("Invalid character: {c}"),
};
let (x, y) = (idx % width, idx / width);
let cell = Cell::new(kind, idx, (x, y));
grid.vec.push(cell);
idx += 1;
}
grid
}
fn find_pos(&self, value: CellType) -> Option<usize> {
self.vec.iter().position(|item| item.kind == value)
}
pub fn print(&self) {
for r in 0usize..self.num_rows() {
let range = self.row_first_idx(r)..=self.row_last_idx(r);
let line: String = self.vec[range]
.iter()
.map(|n| (n.get_height() + b'a') as char)
.collect();
println!("{}", line);
}
}
fn get_index_for_move(&self, from: usize, dir: Direction) -> Option<usize> {
let (mut x, mut y) = self.idx_xy(from);
match dir {
Direction::Up => {
if y >= 1 {
y -= 1;
} else {
return None;
}
}
Direction::Down => {
if y < self.num_rows() - 1 {
y += 1;
} else {
return None;
}
}
Direction::Left => {
if x >= 1 {
x -= 1;
} else {
return None;
}
}
Direction::Right => {
if x < self.num_cols() - 1 {
x += 1;
} else {
return None;
}
}
};
Some(self.xy_idx(x, y))
}
fn is_valid_move(&self, start: usize, end: usize) -> bool {
// Is the item within the grid?
let start_char = self.get(start);
let end_char = self.get(end);
if start_char.is_none() || end_char.is_none() {
return false;
}
let start_char = start_char.unwrap();
let end_char = end_char.unwrap();
let start_elevation = start_char.get_height();
let end_elevation = end_char.get_height();
if (end_elevation < start_elevation) || end_elevation.abs_diff(start_elevation) > 1 {
return false;
}
let ((start_x, start_y), (end_x, end_y)) = (start_char.coord, end_char.coord);
let x_diff = end_x.abs_diff(start_x);
let y_diff = end_y.abs_diff(start_y);
// Have we moved 0 or 1 in a cardinal direction?
matches!((x_diff, y_diff), (0, 0) | (0, 1) | (1, 0))
}
fn find_moves(&self, start: usize) -> Vec<usize> {
[
Direction::Up,
Direction::Down,
Direction::Left,
Direction::Right,
]
.into_iter()
.filter_map(|d| self.get_index_for_move(start, d))
.collect()
}
fn find_valid_moves(&self, start: usize) -> Vec<usize> {
self.find_moves(start)
.into_iter()
.filter(|m| self.is_valid_move(start, *m))
.collect()
}
fn has_valid_neighbor(&self, idx: usize) -> bool {
!self.find_valid_moves(idx).is_empty()
}
}
impl fmt::Debug for Grid<Cell> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
for r in 0usize..self.num_rows() {
let range = self.row_first_idx(r)..=self.row_last_idx(r);
let line: String = self.vec[range]
.iter()
.map(|n| (n.get_height() + b'a') as char)
.collect();
writeln!(f, "{}", line)?;
}
Ok(())
}
}
// ----------------------------------------------------------------------------
#[derive(Debug)]
pub struct Pathfinder {
start_idx: usize,
end_idx: usize,
grid: Grid<Cell>,
tree: Node,
}
impl Pathfinder {
pub fn from_file_str(file_str: &str) -> Self {
let mut pf = Pathfinder {
start_idx: 0,
end_idx: 0,
grid: Grid::from_file_str(file_str),
tree: Node::default(),
};
let start = pf.grid.find_pos(CellType::Start).unwrap();
let end = pf.grid.find_pos(CellType::End).unwrap();
pf.start_idx = start;
pf.end_idx = end;
pf.tree.idx = start;
pf
}
fn add_children(&mut self, node: &mut Node, idx: usize) {
let possible_moves = self.grid.find_valid_moves(idx);
if possible_moves.is_empty() {
return;
}
for m in possible_moves {
if node.contains(m) {
continue;
}
let n = node.add_child(m);
if m != self.end_idx {
self.add_children(n, m);
} else {
break;
}
}
}
fn build_tree(&mut self) {
let mut tree = { self.tree.clone() };
let idx = { self.start_idx };
self.add_children(&mut tree, idx);
self.tree = tree;
}
fn get_paths(&self) -> impl Iterator<Item = &Node> {
self.tree
.get_leaves()
.into_iter()
.filter(|n| n.idx == self.end_idx)
}
pub fn find_shortest_path(&mut self) -> &Node {
self.build_tree();
self.get_paths()
.min_by(|a, b| a.get_len().cmp(&b.get_len()))
.unwrap()
}
}
#[cfg(test)]
mod tests {
use super::*;
fn get_test_data() -> &'static str {
include_str!("test-input.txt")
}
fn get_finder() -> Pathfinder {
Pathfinder::from_file_str(get_test_data())
}
#[test]
fn find_valid_moves() {
let finder = get_finder();
assert_eq!(finder.grid.find_valid_moves(finder.start_idx), vec![8, 1]);
assert_eq!(finder.grid.find_valid_moves(8), vec![0, 16, 9]);
}
#[test]
fn find_shortest_path() {
let mut finder = get_finder();
let shortest = finder.find_shortest_path();
assert_eq!(shortest.get_len(), 31);
}
}

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@ -1,281 +1,7 @@
mod node;
use node::Node;
use aoc_shared::enums::Direction;
use aoc_shared::grid::Grid as BaseGrid;
use aoc_shared::impl_grid_newtype;
#[derive(Debug, Copy, Clone, PartialEq)]
enum CellType {
Start,
End,
Waypoint(u8),
}
#[derive(Debug, Clone)]
struct Cell {
kind: CellType,
idx: usize,
coord: (usize, usize),
}
impl Cell {
pub fn new(kind: CellType, idx: usize, coord: (usize, usize)) -> Self {
Cell { kind, idx, coord }
}
pub fn get_height(&self) -> u8 {
match self.kind {
CellType::Start => 0,
CellType::End => 25,
CellType::Waypoint(c) => c,
}
}
}
// ----------------------------------------------------------------------------
#[derive(Debug)]
pub struct Grid<T>(BaseGrid<T>);
impl_grid_newtype!(Grid, BaseGrid<Cell>, Cell);
impl Grid<Cell> {
pub fn from_file_str(file_str: &str) -> Self {
let first_line = file_str.lines().next().unwrap();
let width = first_line.len();
let mut grid = Grid::new(width);
let mut idx = 0usize;
for c in file_str.chars() {
let kind = match c {
'S' => CellType::Start,
'E' => CellType::End,
'a'..='z' => CellType::Waypoint(c as u8 - b'a'),
'\r' | '\n' => continue,
_ => panic!("Invalid character: {c}"),
};
let (x, y) = (idx % width, idx / width);
let cell = Cell::new(kind, idx, (x, y));
grid.vec.push(cell);
idx += 1;
}
grid
}
fn find_pos(&self, value: CellType) -> Option<usize> {
self.vec.iter().position(|item| item.kind == value)
}
pub fn print(&self) {
for r in 0usize..self.num_rows() {
let range = self.row_first_idx(r)..=self.row_last_idx(r);
let line: String = self.vec[range]
.iter()
.map(|n| (n.get_height() + b'a') as char)
.collect();
println!("{}", line);
}
}
fn get_index_for_move(&self, from: usize, dir: Direction) -> Option<usize> {
let (mut x, mut y) = self.idx_xy(from);
match dir {
Direction::Up => {
if y >= 1 {
y -= 1;
} else {
return None;
}
}
Direction::Down => {
if y < self.num_rows() - 1 {
y += 1;
} else {
return None;
}
}
Direction::Left => {
if x >= 1 {
x -= 1;
} else {
return None;
}
}
Direction::Right => {
if x < self.num_cols() - 1 {
x += 1;
} else {
return None;
}
}
};
Some(self.xy_idx(x, y))
}
fn is_valid_move(&self, start: usize, end: usize) -> bool {
// Is the item within the grid?
let start_char = self.get(start);
let end_char = self.get(end);
if start_char.is_none() || end_char.is_none() {
return false;
}
let start_char = start_char.unwrap();
let end_char = end_char.unwrap();
let start_elevation = start_char.get_height();
let end_elevation = end_char.get_height();
if (end_elevation < start_elevation) || end_elevation.abs_diff(start_elevation) > 1 {
return false;
}
let ((start_x, start_y), (end_x, end_y)) = (start_char.coord, end_char.coord);
let x_diff = end_x.abs_diff(start_x);
let y_diff = end_y.abs_diff(start_y);
// Have we moved 0 or 1 in a cardinal direction?
matches!((x_diff, y_diff), (0, 0) | (0, 1) | (1, 0))
}
fn find_moves(&self, start: usize) -> Vec<usize> {
[
Direction::Up,
Direction::Down,
Direction::Left,
Direction::Right,
]
.into_iter()
.filter_map(|d| self.get_index_for_move(start, d))
.collect()
}
fn find_valid_moves(&self, start: usize) -> Vec<usize> {
self.find_moves(start)
.into_iter()
.filter(|m| self.is_valid_move(start, *m))
.collect()
}
fn has_valid_neighbor(&self, idx: usize) -> bool {
!self.find_valid_moves(idx).is_empty()
}
}
// ----------------------------------------------------------------------------
#[derive(Debug)]
pub struct Pathfinder {
start_idx: usize,
end_idx: usize,
grid: Grid<Cell>,
tree: Node,
}
impl Pathfinder {
pub fn from_file_str(file_str: &str) -> Self {
let mut pf = Pathfinder {
start_idx: 0,
end_idx: 0,
grid: Grid::from_file_str(file_str),
tree: Node::default(),
};
let start = pf.grid.find_pos(CellType::Start).unwrap();
let end = pf.grid.find_pos(CellType::End).unwrap();
pf.start_idx = start;
pf.end_idx = end;
pf.tree.idx = start;
pf
}
fn add_children(&mut self, node: &mut Node, idx: usize) {
let possible_moves = self.grid.find_valid_moves(idx);
if possible_moves.is_empty() {
return;
}
for m in possible_moves {
if node.contains(m) {
continue;
}
let n = node.add_child(m);
if m != self.end_idx {
self.add_children(n, m);
} else {
break;
}
}
}
fn build_tree(&mut self) {
let mut tree = { self.tree.clone() };
let idx = { self.start_idx };
self.add_children(&mut tree, idx);
self.tree = tree;
}
fn get_paths(&self) -> impl Iterator<Item = &Node> {
self.tree
.get_leaves()
.into_iter()
.filter(|n| n.idx == self.end_idx)
}
pub fn find_shortest_path(&mut self) -> &Node {
self.build_tree();
self.get_paths()
.min_by(|a, b| a.get_len().cmp(&b.get_len()))
.unwrap()
}
}
// ----------------------------------------------------------------------------
fn main() { fn main() {
let file_str = include_str!("input.txt"); let file_str = include_str!("input.txt");
let mut finder = Pathfinder::from_file_str(file_str); let mut finder = ::day12::Pathfinder::from_file_str(file_str);
let shortest_path = finder.find_shortest_path(); let shortest_path = finder.find_shortest_path();
println!("Part 1: Fewest steps: {}", shortest_path.get_len()); println!("Part 1: Fewest steps: {}", shortest_path.get_len());
} }
#[cfg(test)]
mod tests {
use super::*;
fn get_test_data() -> &'static str {
include_str!("test-input.txt")
}
fn get_finder() -> Pathfinder {
Pathfinder::from_file_str(get_test_data())
}
#[test]
fn find_valid_moves() {
let finder = get_finder();
assert_eq!(finder.grid.find_valid_moves(finder.start_idx), vec![8, 1]);
assert_eq!(finder.grid.find_valid_moves(8), vec![0, 16, 9]);
}
#[test]
fn find_shortest_path() {
let mut finder = get_finder();
let shortest = finder.find_shortest_path();
assert_eq!(shortest.get_len(), 31);
}
}

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@ -20,9 +20,7 @@ impl Node {
self.append(child); self.append(child);
self.children self.children.last_mut().unwrap()
.last_mut()
.unwrap()
} }
fn append(&mut self, node: Node) -> &mut Self { fn append(&mut self, node: Node) -> &mut Self {
@ -50,9 +48,7 @@ impl Node {
let mut leaves = Vec::new(); let mut leaves = Vec::new();
let children = self let children = self.children.iter();
.children
.iter();
for child in children { for child in children {
let mut child_leaves = child.get_leaves(); let mut child_leaves = child.get_leaves();