Řešení KSP úlohy 33-3-4 Obsazování území
https://ksp.mff.cuni.cz/h/ulohy/33/zadani3.html#task-33-3-4
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608 lines
20 KiB
608 lines
20 KiB
use rand::prelude::{StdRng, SliceRandom};
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use rand::{SeedableRng, Rng, thread_rng};
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use std::fmt;
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use std::fmt::Formatter;
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use std::collections::{HashMap, HashSet};
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pub const SIZE: usize = 16384;
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pub const HOUSE_RANGE: usize = 500;
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pub struct City {
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prices: Vec<u16>,
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buyable_house_count: usize
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}
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impl City {
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pub fn read_from_file(filename: &str) -> Self {
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let values = std::fs::read(filename).unwrap();
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let mut prices: Vec<u16> = Vec::new();
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for y in 0..SIZE {
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for x in 0..SIZE {
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let price = (values[(y * SIZE + x) * 2] as u16) | ((values[(y * SIZE + x) * 2 + 1] as u16) << 8);
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prices.push(price);
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}
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}
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City::new(prices)
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}
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pub fn new(prices: Vec<u16>) -> Self {
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let mut buyable_house_count = 0;
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for &price in &prices {
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if price > 0 {
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buyable_house_count += 1;
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}
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}
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City { prices, buyable_house_count }
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}
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pub fn get_price(&self, house: &House) -> u16 {
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self.prices[house.y * SIZE + house.x]
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}
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pub fn get_price_xy(&self, x: usize, y: usize) -> u16 {
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self.prices[y * SIZE + x]
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}
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pub fn is_house(&self, house: &House) -> bool {
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self.get_price(&house) > 0
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}
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pub fn is_house_xy(&self, x: usize, y: usize) -> bool {
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self.get_price_xy(x, y) > 0
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}
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pub fn get_house_count(&self) -> usize {
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self.buyable_house_count
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}
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}
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#[derive(Eq, PartialEq, Hash, Copy, Clone)]
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pub struct House {
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x: usize,
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y: usize,
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}
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impl House {
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pub fn new(x: usize, y: usize) -> Self {
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House { x, y }
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}
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pub fn range_rectangle(&self) -> Rectangle {
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let top = if self.y <= HOUSE_RANGE { 0 } else { self.y - HOUSE_RANGE };
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let bottom = if self.y >= SIZE - 1 - HOUSE_RANGE { SIZE - 1 } else { self.y + HOUSE_RANGE };
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let left = if self.x <= HOUSE_RANGE { 0 } else { self.x - HOUSE_RANGE };
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let right = if self.x >= SIZE - 1 - HOUSE_RANGE { SIZE - 1 } else { self.x + HOUSE_RANGE };
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Rectangle {top, bottom, left, right}
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}
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}
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/// Rectangle - a 2D range with inclusive bounds
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pub struct Rectangle {
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/// The smaller x coordinate.
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left: usize,
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/// The bigger x coordinate.
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right: usize,
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/// The smaller y coordinate.
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top: usize,
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/// The bigger y coordinate.
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bottom: usize,
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}
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impl fmt::Display for Rectangle {
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fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
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write!(f, "L{}-{}R T{}-{}B", self.left, self.right, self.top, self.bottom)
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}
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}
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impl Rectangle {
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pub fn is_inside(&self, x: usize, y: usize) -> bool {
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self.left <= x && x <= self.right && self.top <= y && y <= self.bottom
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}
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pub fn width(&self) -> usize {
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self.right - self.left
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}
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pub fn height(&self) -> usize {
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self.bottom - self.top
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}
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}
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pub struct HouseLayout<'a> {
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city: &'a City,
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reachable: Vec<u16>,
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houses: Vec<House>,
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reachable_houses: usize
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}
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impl<'a> HouseLayout<'a> {
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pub fn new(city: &'a City) -> Self {
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HouseLayout { city, reachable: vec![0; SIZE * SIZE], houses: Vec::new(), reachable_houses: 0 }
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}
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pub fn cover_count(&self, house: House) -> u16 {
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self.reachable[house.y * SIZE + house.x]
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}
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pub fn cover_count_xy(&self, x: usize, y: usize) -> u16 {
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self.reachable[y * SIZE + x]
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}
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pub fn is_covered(&self, house: House) -> bool {
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self.cover_count(house) > 0
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}
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pub fn add_house(&mut self, house: House) -> usize {
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let range_rect = house.range_rectangle();
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for y in range_rect.top..=range_rect.bottom {
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for x in range_rect.left..=range_rect.right {
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let index = y as usize * SIZE + x as usize;
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if self.reachable[index] == 0 && self.city.is_house_xy(x as usize, y as usize) {
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self.reachable_houses += 1;
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}
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self.reachable[index] += 1;
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}
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}
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self.houses.push(house);
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self.houses.len() - 1
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}
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pub fn remove_house(&mut self, index: usize) {
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let house = self.houses.swap_remove(index);
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let range_rect = house.range_rectangle();
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for y in range_rect.top..=range_rect.bottom {
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for x in range_rect.left..=range_rect.right {
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let index = y as usize * SIZE + x as usize;
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self.reachable[index] -= 1;
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if self.reachable[index] == 0 && self.city.is_house_xy(x as usize, y as usize) {
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self.reachable_houses -= 1;
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}
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}
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}
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}
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pub fn is_valid(&self) -> bool {
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self.reachable_houses == self.city.buyable_house_count
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}
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pub fn price(&self) -> u32 {
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get_price(self.city, &self.houses)
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}
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pub fn houses(&self) -> &Vec<House> {
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&self.houses
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}
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}
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fn dump_layout(layout: &HouseLayout, best_price: &mut Option<u32>, seed: u64) {
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let price = layout.price();
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if best_price.is_none() || price < best_price.unwrap() {
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*best_price = Some(price);
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eprintln!("Printing {} - new best", price);
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println!("New best!");
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println!("Price {}, seed {}", price, seed);
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print_houses(&layout.houses());
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println!();
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} else {
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eprintln!("Printing {}", price);
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println!("Price {}, seed {}", price, seed);
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print_houses(&layout.houses());
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println!();
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}
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}
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fn main() {
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let city = City::read_from_file("01.in");
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let mut best_price: Option<u32> = None;
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loop {
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let seed: u64 = thread_rng().gen();
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eprintln!("Starting seed {}", seed);
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let mut rng = StdRng::seed_from_u64(seed);
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let mut layout = HouseLayout::new(&city);
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eprintln!("Starting random population...");
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populate_random(&mut layout, &mut rng);
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eprintln!("Finished random init, price: {}", layout.price());
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loop {
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let mut improved = false;
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eprintln!("Starting moving individual houses...");
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if improve_move_individual_houses(&mut layout, &mut rng) {
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dump_layout(&layout, &mut best_price, seed);
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improved = true;
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}
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eprintln!("Finished moving individual houses...");
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eprintln!("Starting pairwise house merge...");
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if improve_merge_pairwise(&mut layout) {
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dump_layout(&layout, &mut best_price, seed);
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improved = true;
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}
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eprintln!("Finished pairwise house merge");
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if !improved {
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break;
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}
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}
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}
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}
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fn populate_random(layout: &mut HouseLayout, rng: &mut StdRng) {
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loop {
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loop {
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let x = rng.gen_range(0..SIZE);
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let y = rng.gen_range(0..SIZE);
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let house = House::new(x, y);
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if layout.city.is_house_xy(x, y) && !layout.is_covered(house) {
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layout.add_house(house);
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break;
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}
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}
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if layout.is_valid() {
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break;
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}
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}
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}
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fn improve_move_individual_houses(layout: &mut HouseLayout, mut rng: &mut StdRng) -> bool {
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let mut improved = false;
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let mut untried_houses = layout.houses().clone();
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untried_houses.shuffle(&mut rng);
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while untried_houses.len() > 0 {
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let house = untried_houses.pop().unwrap();
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let house_index = layout.houses().iter().position(|x| *x == house).unwrap();
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let move_rectangle = match get_valid_move_rectangle(&layout, house) {
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Ok(move_rectangle) => move_rectangle,
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Err(RectangleSearchError::Useless) => {
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//let old_price = layout.price();
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layout.remove_house(house_index);
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//let new_price = layout.price();
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//let price_diff = new_price as i64 - old_price as i64;
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//eprintln!(" candidate is valid, price diff: {}.", price_diff);
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//eprintln!("Removed a house (useless), diff {}", price_diff);
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//eprintln!("Improved price: {}", new_price);
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improved = true;
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untried_houses = layout.houses().clone();
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untried_houses.shuffle(&mut rng);
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continue;
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}
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_ => unreachable!()
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};
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// TODO: Not needed, can just store best
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let mut new_candidates = Vec::new();
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for new_y in move_rectangle.top..=move_rectangle.bottom {
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for new_x in move_rectangle.left..=move_rectangle.right {
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if layout.city.is_house_xy(new_x, new_y) && layout.city.get_price_xy(new_x, new_y) < layout.city.get_price(&house) {
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new_candidates.push(House::new(new_x, new_y));
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}
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}
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}
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new_candidates.sort_by(|a, b| layout.city.get_price(&a).cmp(&layout.city.get_price(&b)));
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if new_candidates.len() == 0 {
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//eprintln!("Did not find candidate");
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} else {
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for (i, &candidate) in new_candidates.iter().enumerate() {
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//eprint!("Found candidate {}...", i);
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//let old_price = layout.price();
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layout.remove_house(house_index);
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layout.add_house(candidate);
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assert!(layout.is_valid());
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//let new_price = layout.price();
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//let price_diff = new_price as i64 - old_price as i64;
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//eprintln!(" candidate is valid, price diff: {}.", price_diff);
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//eprintln!("Improved price: {}", new_price);
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improved = true;
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untried_houses = layout.houses().clone();
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untried_houses.shuffle(&mut rng);
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break;
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}
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}
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}
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improved
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}
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pub fn improve_merge_pairwise(layout: &mut HouseLayout) -> bool {
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let mut improved = false;
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loop {
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// This here is a hack for being unable to modify the houses while looping through them.
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// We instead go through the houses repeatedly and remember which pairs we have already
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// tried by hashing their values because they can and do move throughout the layout Vec
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// as it's being modified.
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let mut checked = HashSet::new();
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let mut loop_improved = false;
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loop {
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let mut merge = None;
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'outer_houses: for i in 0..layout.houses().len() {
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for j in i + 1..layout.houses().len() {
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let house1 = layout.houses()[i];
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let house2 = layout.houses()[j];
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let x_dist = (house1.x as i32 - house2.x as i32).abs() as usize;
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let y_dist = (house1.y as i32 - house2.y as i32).abs() as usize;
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if x_dist > 4 * HOUSE_RANGE || y_dist > 4 * HOUSE_RANGE {
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// Never close enough to merge
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continue;
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}
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if checked.contains(&(house1, house2)) || checked.contains(&(house2, house1)) {
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continue;
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} else {
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checked.insert((house1, house2));
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}
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match get_valid_move_rectangle_multiple(&layout, &vec! {house1, house2}) {
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Ok(rect) => {
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let mut cheapest = None;
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for y in rect.top..=rect.bottom {
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for x in rect.left..=rect.right {
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if !layout.city.is_house_xy(x, y) { continue; }
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let price = layout.city.get_price_xy(x, y);
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match cheapest {
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None => cheapest = Some((x, y, price)),
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Some((_, _, cheapest_price)) if price < cheapest_price => cheapest = Some((x, y, price)),
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_ => {}
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};
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}
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}
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if let Some((x, y, price)) = cheapest {
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if price >= layout.city.get_price(&house1) + layout.city.get_price(&house2) {
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// Merging not worth
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//eprintln!("Merging not worth!");
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} else {
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merge = Some((i, j, House::new(x, y)));
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break 'outer_houses;
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}
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}
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}
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Err(RectangleSearchError::Useless) => eprintln!("Found useless pair of houses, not solving!"),
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Err(RectangleSearchError::Unsatisfiable) => {}
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}
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}
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}
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if let Some((i, j, house)) = merge {
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let old_price = layout.price();
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assert!(i < j);
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layout.remove_house(j);
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layout.remove_house(i);
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layout.add_house(house);
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assert!(layout.is_valid());
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let new_price = layout.price();
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let price_diff = new_price as i32 - old_price as i32;
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eprintln!("Merged two houses, new price {}, diff {}", new_price, price_diff);
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improved = true;
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loop_improved = true;
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} else {
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break;
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}
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}
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if !loop_improved {
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break;
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}
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}
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improved
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}
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pub enum RectangleSearchError {
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Useless,
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Unsatisfiable
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}
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pub fn get_valid_move_rectangle_multiple(layout: &HouseLayout, houses: &Vec<House>) -> Result<Rectangle, RectangleSearchError> {
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// This is a generalization of get_valid_move_rectangle, it's basically the same thing,
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// just with a dynamic rectangles_containing_count
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// We first establish a bounding box for an that has to be covered if all houses are removed.
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let mut covered_rect: Option<Rectangle> = None;
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for house in houses {
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let range_rect = house.range_rectangle();
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for y in range_rect.top..=range_rect.bottom {
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for x in range_rect.left..=range_rect.right {
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// We count how many rectangles of houses contain this xy position.
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let mut rectangles_containing_count = 0;
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for house in houses {
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let rect = house.range_rectangle();
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if rect.is_inside(x, y) {
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rectangles_containing_count += 1;
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}
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}
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// If this house is covered by the exact amount of rectangles,
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// then removing all input houses would uncover this position.
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// It cannot be less than the rectangle count, and more means there
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// is another house covering it as well.
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if layout.cover_count_xy(x, y) == rectangles_containing_count && layout.city.is_house_xy(x, y) {
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if let Some(cover) = &mut covered_rect {
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cover.left = cover.left.min(x);
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cover.right = cover.right.max(x);
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cover.top = cover.top.min(y);
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cover.bottom = cover.bottom.max(y);
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} else {
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covered_rect = Some(Rectangle { left: x, right: x, top: y, bottom: y });
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}
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}
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}
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}
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};
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if covered_rect.is_none() {
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// Unnecessary set of houses.
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return Err(RectangleSearchError::Useless);
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}
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let covered_rect = covered_rect.unwrap();
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let height_margin = HOUSE_RANGE as i32 - covered_rect.height() as i32;
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let width_margin = HOUSE_RANGE as i32 - covered_rect.width() as i32;
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let top = (covered_rect.top as i32 - height_margin).max(0) as usize;
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let left = (covered_rect.left as i32 - width_margin).max(0) as usize;
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let bottom = (covered_rect.bottom + height_margin as usize).min(SIZE - 1);
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let right = (covered_rect.right + width_margin as usize).min(SIZE - 1);
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if top > bottom || left > right {
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// Unsatisfiable rectangle by one house
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return Err(RectangleSearchError::Unsatisfiable);
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}
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Ok(Rectangle { left, right, top, bottom })
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}
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pub fn get_valid_move_rectangle(layout: &HouseLayout, house: House) -> Result<Rectangle, RectangleSearchError> {
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// We first establish a bounding box for an that has to be covered if the house is removed.
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let mut covered_rect: Option<Rectangle> = None;
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let range_rect = house.range_rectangle();
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for y in range_rect.top..=range_rect.bottom {
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for x in range_rect.left..=range_rect.right {
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if layout.cover_count_xy(x, y) == 1 && layout.city.is_house_xy(x, y) {
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// This house is only covered by the house, it has to be covered from the new position as well.
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if let Some(cover) = &mut covered_rect {
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cover.left = cover.left.min(x);
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cover.right = cover.right.max(x);
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cover.top = cover.top.min(y);
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cover.bottom = cover.bottom.max(y);
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} else {
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covered_rect = Some(Rectangle { left: x, right: x, top: y, bottom: y });
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}
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}
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}
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}
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if covered_rect.is_none() {
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return Err(RectangleSearchError::Useless)
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}
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let covered_rect = covered_rect.unwrap();
|
|
|
|
// The distance of the rectangle from the original box tells us how much the house can move.
|
|
let dist_left = covered_rect.left - range_rect.left;
|
|
let dist_right = range_rect.right - covered_rect.right;
|
|
let dist_top = covered_rect.top - range_rect.top;
|
|
let dist_bottom = range_rect.bottom - covered_rect.bottom;
|
|
|
|
let left = if house.x <= dist_right { 0 } else { house.x - dist_right };
|
|
let right = if house.x >= SIZE - 1 - dist_left { SIZE - 1 } else { house.x + dist_left };
|
|
let top = if house.y <= dist_bottom { 0 } else { house.y - dist_bottom };
|
|
let bottom = if house.y >= SIZE - 1 - dist_top { SIZE - 1 } else { house.y + dist_top };
|
|
|
|
let valid_move_rectangle = Rectangle {
|
|
left, right, top, bottom
|
|
};
|
|
|
|
Ok(valid_move_rectangle)
|
|
}
|
|
|
|
pub fn get_neighbors(city: &City, house: &House) -> Vec<House> {
|
|
let mut neighbors = Vec::new();
|
|
let range_rect = house.range_rectangle();
|
|
for y in range_rect.top..=range_rect.bottom {
|
|
for x in range_rect.left..=range_rect.right {
|
|
let house = House::new(x as usize, y as usize);
|
|
if city.get_price(&house) > 0 {
|
|
neighbors.push(house);
|
|
}
|
|
}
|
|
}
|
|
|
|
neighbors
|
|
}
|
|
|
|
fn print_houses(houses: &Vec<House>) {
|
|
println!("{}", houses.len());
|
|
for house in houses {
|
|
println!("{} {}", house.y, house.x);
|
|
}
|
|
}
|
|
|
|
fn get_price(city: &City, houses: &Vec<House>) -> u32 {
|
|
let mut price = 0u32;
|
|
for house in houses {
|
|
price += city.get_price(&house) as u32;
|
|
}
|
|
|
|
price
|
|
}
|
|
|
|
fn is_valid(city: &City, houses: &Vec<House>) -> Option<u32> {
|
|
let mut reachable = vec![false; SIZE * SIZE];
|
|
let mut price = 0u32;
|
|
|
|
for house in houses {
|
|
assert!(city.prices[house.y * SIZE + house.x] > 0);
|
|
|
|
let range_rect = house.range_rectangle();
|
|
for y in range_rect.top..=range_rect.bottom {
|
|
for x in range_rect.left..=range_rect.right {
|
|
reachable[y as usize * SIZE + x as usize] = true;
|
|
}
|
|
}
|
|
price += city.get_price(&house) as u32;
|
|
}
|
|
|
|
for y in 0..SIZE {
|
|
for x in 0..SIZE {
|
|
if !reachable[y * SIZE + x] && city.prices[y * SIZE + x] > 0 {
|
|
return None;
|
|
}
|
|
}
|
|
}
|
|
|
|
Some(price)
|
|
}
|
|
|
|
#[cfg(test)]
|
|
mod tests {
|
|
use super::*;
|
|
|
|
#[test]
|
|
fn house_rectangle_at_min() {
|
|
let house = House::new(0, 0);
|
|
let rect = house.range_rectangle();
|
|
assert_eq!(rect.top, 0);
|
|
assert_eq!(rect.left, 0);
|
|
assert_eq!(rect.right, HOUSE_RANGE);
|
|
assert_eq!(rect.bottom, HOUSE_RANGE);
|
|
}
|
|
|
|
#[test]
|
|
fn house_rectangle_at_max() {
|
|
let house = House::new(SIZE - 1, SIZE - 1);
|
|
let rect = house.range_rectangle();
|
|
assert_eq!(rect.top, SIZE - 1 - HOUSE_RANGE);
|
|
assert_eq!(rect.left, SIZE - 1 - HOUSE_RANGE);
|
|
assert_eq!(rect.right, SIZE - 1);
|
|
assert_eq!(rect.bottom, SIZE - 1);
|
|
}
|
|
|
|
#[test]
|
|
fn house_rect_in_middle() {
|
|
let house = House::new(SIZE / 2, SIZE / 2);
|
|
let rect = house.range_rectangle();
|
|
assert_eq!(rect.top, house.y - HOUSE_RANGE);
|
|
assert_eq!(rect.left, house.x - HOUSE_RANGE);
|
|
assert_eq!(rect.right, house.x + HOUSE_RANGE);
|
|
assert_eq!(rect.bottom, house.y + HOUSE_RANGE);
|
|
}
|
|
}
|