Random generation

Cargo.lock

@@ -0,0 +1,90 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
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+ "cfg-if",
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+]
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Cargo.toml

@@ -0,0 +1,11 @@
+[package]
+name = "prague"
+version = "0.1.0"
+authors = ["Jiří Sejkora <sejsel@sejsel.cz>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+byteorder = "1.3.4"
+rand = "0.8.0"

src/main.rs

@@ -0,0 +1,159 @@
+use std::fs::File;
+use byteorder::{LittleEndian, ReadBytesExt};
+use rand::prelude::StdRng;
+use rand::{SeedableRng, Rng, thread_rng};
+
+const SIZE: usize = 16384;
+
+struct City {
+    prices: Vec<u16>,
+    buyable_house_count: usize
+}
+
+impl City {
+    pub fn new(prices: Vec<u16>) -> Self {
+        let mut buyable_house_count = 0;
+        for &price in &prices {
+            if price > 0 {
+                buyable_house_count += 1;
+            }
+        }
+        City { prices, buyable_house_count }
+    }
+
+    pub fn get_price(&self, house: &House) -> u16 {
+        self.prices[house.y * SIZE + house.x]
+    }
+
+    pub fn is_house(&self, house: &House) -> bool {
+        self.get_price(&house) > 0
+    }
+
+    pub fn get_house_count(&self) -> usize {
+        self.buyable_house_count
+    }
+}
+
+struct House {
+    x: usize,
+    y: usize,
+}
+
+impl House {
+    pub fn new(x: usize, y: usize) -> Self {
+        House { x, y }
+    }
+}
+
+fn main() {
+    let values = std::fs::read("01.in").unwrap();
+    let mut prices: Vec<u16> = Vec::new();
+
+    for y in 0..SIZE {
+        for x in 0..SIZE {
+            let price = (values[(y * SIZE + x) * 2] as u16) | ((values[(y * SIZE + x) * 2] as u16) << 8);
+            prices.push(price);
+        }
+    }
+
+    let city = City::new(prices);
+    println!("Created city");
+
+    loop {
+        let seed: u64 = thread_rng().gen();
+        eprintln!("Starting seed {}", seed);
+
+        let mut rng = StdRng::seed_from_u64(seed);
+        let mut reachable = vec![false; SIZE * SIZE];
+        let mut houses: Vec<House> = Vec::new();
+        let mut claimed_houses = 0;
+        loop {
+            loop {
+                let x = rng.gen_range(0..SIZE);
+                let y = rng.gen_range(0..SIZE);
+                let house = House::new(x, y);
+                if city.is_house(&house) && !reachable[y * SIZE + x] {
+                    for y in (house.y as i32 - 500).max(0)..=(house.y as i32 + 500).min((SIZE - 1) as i32) {
+                        for x in (house.x as i32 - 500).max(0)..=(house.x as i32 + 500).min((SIZE - 1) as i32) {
+                            let index = y as usize * SIZE + x as usize;
+                            if !reachable[index] {
+                                reachable[index] = true;
+                                if city.is_house(&House::new(x as usize, y as usize)) {
+                                    claimed_houses += 1;
+                                }
+                            }
+                        }
+                    }
+                    houses.push(house);
+                    //eprintln!("{} houses", houses.len());
+                    break;
+                }
+            }
+
+            let finished = claimed_houses == city.get_house_count();
+
+            if finished {
+                let price = get_price(&city, &houses);
+                eprintln!("Price: {}", price);
+                //print_houses(&houses);
+                break;
+            }
+        }
+    }
+}
+
+fn get_neighbors(city: &City, house: &House) -> Vec<House> {
+    let mut neighbors = Vec::new();
+    for y in (house.y as i32 - 500).max(0)..=(house.y as i32 + 500).min((SIZE - 1) as i32) {
+        for x in (house.x as i32 - 500).max(0)..=(house.x as i32 + 500).min((SIZE - 1) as i32) {
+            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>) {
+    eprintln!("{}", houses.len());
+    for house in houses {
+        eprintln!("{} {}", 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);
+
+        for y in (house.y as i32 - 500).max(0)..=(house.y as i32 + 500).min((SIZE - 1) as i32) {
+            for x in (house.x as i32 - 500).max(0)..=(house.x as i32 + 500).min((SIZE - 1) as i32) {
+                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)
+}