Day 17 part 1

Cargo.lock

@@ -15,6 +15,7 @@ dependencies = [
 name = "aoc_2018"
 version = "0.1.0"
 dependencies = [
+ "bmp",
  "chrono",
  "gcd",
  "itertools",
@@ -22,6 +23,21 @@ dependencies = [
  "regex",
 ]
 
+[[package]]
+name = "bmp"
+version = "0.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "69985ff4f58085ac696454692d0b646a66ad1f9cc9be294c91dc51bb5df511ae"
+dependencies = [
+ "byteorder",
+]
+
+[[package]]
+name = "byteorder"
+version = "1.4.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "14c189c53d098945499cdfa7ecc63567cf3886b3332b312a5b4585d8d3a6a610"
+
 [[package]]
 name = "cfg-if"
 version = "0.1.6"

Cargo.toml

@@ -10,3 +10,4 @@ chrono = "0.4.6"
 itertools = "0.7.11"
 gcd = "1.1.0"
 lazy_static = "1.2.0"
+bmp = "0.5.0"

src/tasks/day17.rs

@@ -1,8 +1,9 @@
+use bmp::Image;
 use itertools::Itertools;
 use regex::Regex;
 
 use crate::utils;
-use std::collections::HashMap;
+use std::{collections::HashMap, fmt::Display};
 
 use Tile::*;
 fn horizontal(line: &str) -> Option<(i32, i32, i32)> {
@@ -28,7 +29,8 @@ fn vertical(line: &str) -> Option<(i32, i32, i32)> {
 }
 pub fn task1() {
     let input = utils::read_file("input/day17.txt");
-    let clay_tiles: HashMap<Pos, Tile> = input.lines().fold(HashMap::new(), |mut tiles, line| {
+    let mut clay_tiles: HashMap<Pos, Tile> =
+        input.lines().fold(HashMap::new(), |mut tiles, line| {
             if let Some((x, y1, y2)) = vertical(line) {
                 for y in y1..=y2 {
                     tiles.insert(Pos(x, y), Clay);
@@ -41,28 +43,142 @@ pub fn task1() {
             }
             tiles
         });
-    let (x_min, x_max) = clay_tiles
-        .keys()
-        .map(|p| p.0)
-        .minmax()
-        .into_option()
-        .unwrap();
     let (y_min, y_max) = clay_tiles
         .keys()
         .map(|p| p.1)
         .minmax()
         .into_option()
         .unwrap();
+
+    flow(&mut clay_tiles, y_max, Pos(500, 0), Pos(500, 0));
+
+    let water_count = clay_tiles
+        .iter()
+        .filter(|(_, tile)| **tile == StuckWater || **tile == FallingWater)
+        .filter(|(p, _)| (y_min..=y_max).contains(&p.1))
+        .count();
+    println!("part 1 water count: {water_count}");
+    // print_tiles(&clay_tiles);
+    // 30605 too low
+    print_bmp(&clay_tiles);
 }
 
+#[allow(dead_code)]
+fn print_tiles(tiles: &HashMap<Pos, Tile>) {
+    let (x_min, x_max) = tiles.keys().map(|p| p.0).minmax().into_option().unwrap();
+    let (_y_min, y_max) = tiles.keys().map(|p| p.1).minmax().into_option().unwrap();
+
+    for y in 0..=y_max {
+        for x in x_min..=x_max {
+            let s = match tiles.get(&Pos(x, y)) {
+                Some(t) => format!("{t}"),
+                None => " ".to_string(),
+            };
+            print!("{s}");
+        }
+        print!("\n");
+    }
+}
+
+fn print_bmp(tiles: &HashMap<Pos, Tile>) {
+    let (x_min, x_max) = tiles.keys().map(|p| p.0).minmax().into_option().unwrap();
+    let (y_min, y_max) = tiles.keys().map(|p| p.1).minmax().into_option().unwrap();
+
+    let mut img = Image::new((x_max - x_min + 1) as u32, (y_max - y_min + 1) as u32);
+    for y in 0..=y_max {
+        for x in x_min..=x_max {
+            let color = match tiles.get(&Pos(x, y)) {
+                Some(t) => match t {
+                    Clay => bmp::consts::BROWN,
+                    FallingWater => bmp::consts::LIGHT_BLUE,
+                    StuckWater => bmp::consts::DARK_BLUE,
+                },
+                None => bmp::consts::WHITE,
+            };
+            img.set_pixel((x - x_min) as u32, (y - y_min) as u32, color);
+        }
+    }
+    img.save("final.bmp").unwrap();
+}
+
+/// returns true iff going left/right and hit a wall
+fn flow(tiles: &mut HashMap<Pos, Tile>, y_max: i32, pos: Pos, from: Pos) -> bool {
+    if pos.1 > y_max {
+        return false;
+    }
+    if let Some(Clay) = tiles.get(&pos) {
+        return true;
+    }
+    if let Some(StuckWater) = tiles.get(&pos) {
+        return true;
+    }
+    if tiles.contains_key(&pos) {
+        return false;
+    }
+
+    tiles.insert(pos, FallingWater);
+    // println!();
+    // print_tiles(tiles);
+    if flow(tiles, y_max, pos.down(), pos) {
+        let bumped_left = flow(tiles, y_max, pos.left(), pos);
+        let bumped_right = flow(tiles, y_max, pos.right(), pos);
+        if from.down() == pos {
+            if bumped_right && bumped_left {
+                fill(tiles, pos);
+                // println!();
+                // print_tiles(tiles);
+                return true;
+            }
+        } else if from.right() == pos && bumped_right {
+            return true;
+        } else if from.left() == pos && bumped_left {
+            return true;
+        }
+    }
+    false
+}
+
+fn fill(tiles: &mut HashMap<Pos, Tile>, pos: Pos) {
+    if let Some(FallingWater) = tiles.get(&pos) {
+        tiles.insert(pos, StuckWater);
+        fill(tiles, pos.left());
+        fill(tiles, pos.right());
+    }
+}
+
+#[derive(PartialEq, Eq)]
 enum Tile {
     Clay,
-    Water,
+    FallingWater,
+    StuckWater,
 }
 
-#[derive(PartialEq, Eq, Hash)]
+impl Display for Tile {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        let s = match self {
+            Clay => "#",
+            FallingWater => "|",
+            StuckWater => "~",
+        };
+        f.write_str(s)
+    }
+}
+
+#[derive(PartialEq, Eq, Hash, Clone, Copy)]
 struct Pos(i32, i32);
 
+impl Pos {
+    fn left(&self) -> Self {
+        Pos(self.0 - 1, self.1)
+    }
+    fn right(&self) -> Self {
+        Pos(self.0 + 1, self.1)
+    }
+    fn down(&self) -> Self {
+        Pos(self.0, self.1 + 1)
+    }
+}
+
 #[cfg(test)]
 mod test {
     use super::*;