day17 pt1

3 files changed, 146 insertions, 42 deletions

diff --git a/input/day17.txt b/input/day17.txt
new file mode 100644
index 0000000..196ade1
--- /dev/null
+++ b/input/day17.txt
@@ -0,0 +1 @@
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\ No newline at end of file
diff --git a/src/day17.rs b/src/day17.rs
index 3606036..da1a6e7 100644
--- a/src/day17.rs
+++ b/src/day17.rs
@@ -1,48 +1,147 @@
+//use std::{thread::{sleep}, time::Duration};
+
 const ROCK: char = '#';
 const AIR: char = '.';
 
-#[derive(Clone,PartialEq)]
+type Grid = Vec<Vec<char>>;
+
+#[derive(Debug,Clone,PartialEq)]
 struct Pos {
-    x: u32,
-    y: u32,
+    x: i32,
+    y: i32,
 }
 
-#[derive(Clone,PartialEq)]
+impl Pos {
+    fn new(x:i32,y:i32) -> Pos {
+        Pos{x, y}
+    }
+    fn translate(&self, other: &Pos) -> Pos {
+        Pos{x: self.x+other.x, y: self.y+other.y}
+    }
+}
+
+/*
+####
+
+.#.
+###
+.#.
+
+..#
+..#
+###
+
+#
+#
+#
+#
+
+##
+##
+*/
+#[derive(Debug,Clone,PartialEq)]
 enum RockType {
     Bar,Cross,Ell,VBar,Square
 }
 
+impl RockType {
+    fn points(&self) -> Vec<Pos> {
+        match self {
+            Self::Bar => vec![Pos::new(0,0), Pos::new(1,0), Pos::new(2,0), Pos::new(3,0)],
+            Self::Cross => vec![Pos::new(1,0), Pos::new(0,1), Pos::new(1,1), Pos::new(2,1), Pos::new(1,2)],
+            Self::Ell => vec![Pos::new(0,0), Pos::new(1,0), Pos::new(2,0), Pos::new(2,1), Pos::new(2,2)],
+            Self::VBar => vec![Pos::new(0,0), Pos::new(0,1), Pos::new(0,2), Pos::new(0,3)],
+            Self::Square => vec![Pos::new(0,0), Pos::new(0,1), Pos::new(1,0), Pos::new(1,1)],
+        }
+    }
+}
+
+#[derive(Debug,Clone,PartialEq)]
 enum Direction {
     Down,Left,Right
 }
 
-#[derive(Clone,PartialEq)]
+impl Direction {
+    fn unit(&self)->Pos {
+        match self {
+            Self::Down => Pos{x:0, y:-1},
+            Self::Left => Pos{x:-1, y:0},
+            Self::Right => Pos{x:1, y:0},
+        }
+    }
+}
+
+#[derive(Debug,Clone,PartialEq)]
 struct Rock {
     rtype: RockType,
-    pos: Pos,
+    pos: Pos, // Position of lower left point in formation
 }
 
 impl Rock {
-    pub fn mv(self, dir: Direction, grid: &Vec<Vec<char>>) -> Self {
-        // Check we _can_ move
-        // Then move
-        self
+    fn points(&self) -> Vec<Pos> {
+        self.rtype.points()
+            .into_iter().map(|p| {p.translate(&self.pos)}).collect()
+    }
+    pub fn mv(self, dir: Direction, grid: &Grid) -> Result<Self,Self> {
+        let width: i32 = grid[0].len() as i32;
+        let du = dir.unit();
+        let np: Vec<Pos> = self.points().into_iter().map(|p| {p.translate(&du)}).collect();
+        if np.iter().any(|p| {
+            // Bounds check 
+            p.y < 0 || 
+            p.x < 0 ||
+            p.x >= width ||
+            // Intersecting another rock?
+            grid[p.y as usize][p.x as usize] != AIR
+        }) {
+            Err(self)
+        } else {
+            let mut nr = self.clone();
+            nr.pos = self.pos.translate(&du);
+            Ok(nr)
+        }
     }
     pub fn solidify(self, grid: &mut Vec<Vec<char>>) {
-        // as it says, transform squares covered by ourselves into solid rock
+        for pt in self.points() {
+            grid[pt.y as usize][pt.x as usize] = ROCK;
+        }
     }
 }
 
-fn rock_height(grid: &Vec<Vec<char>>) -> usize {
-    0
+fn rock_height(grid: &Grid) -> usize {
+    grid.iter().enumerate()
+        .rfind(|row| {
+            row.1.iter().any(|cell| {*cell == ROCK})
+        })
+        .map(|row| {
+            row.0+1 // height is one more than the index..
+        })
+        .unwrap_or(0)
 }
 
-fn run(input: String) {
+// fn print(grid: &Grid, rock: &Rock, rock_count: usize) {
+//     print!("{}[2J", 27 as char); // clear terminal!
+//     println!("+++++++");
+//     let pts = rock.points();
+//     for (y ,row) in grid.iter().enumerate().rev() {
+//         for (x, cell) in row.iter().enumerate() {
+//             if pts.contains(&Pos{x:(x as i32),y:(y as i32)}) {
+//                 print!("@");
+//             } else {
+//                 print!("{}", cell);
+//             }
+//         }
+//         print!("\n");
+//     }
+//     println!("+++++++ height: {} rocks: {}", rock_height(grid), rock_count);
+// }
+
+pub fn run(input: String) {
     let initial_height = 6;
     let width = 7;
-    let rocks = vec![RockType::Bar,RockType::Cross,RockType::Ell,RockType::VBar,RockType::Square].into_iter().cycle();
-    let gas_jets = input.chars().cycle();
-    let mut grid: Vec<Vec<char>> = (0..initial_height).map(|_| {
+    let mut rocks = vec![RockType::Bar,RockType::Cross,RockType::Ell,RockType::VBar,RockType::Square].into_iter().cycle();
+    let mut gas_jets = input.chars().cycle();
+    let mut grid: Grid = (0..initial_height).map(|_| {
         (0..width).map(|_| {AIR}).collect()
     }).collect();
 
@@ -52,36 +151,40 @@ fn run(input: String) {
     };
     let mut rocks_count: usize = 1;
     'lp: loop {
-        let mv = match gas_jets.next().unwrap() {
+        let push = match gas_jets.next().unwrap() {
             '>' => Direction::Right,
             '<' => Direction::Left,
             dir => panic!("Unexpected jet direction! {}", dir)
         };
-        // apply jet, ignore if it didn't move
-        let r2 = rock.mv(mv, &grid);
+        // apply jet, ignore any error.
+        rock = rock.mv(push, &grid).unwrap_or_else(|e| {e});
         // apply gravity
-        let r3 = r2.mv(Direction::Down, &grid);
-
-        if rock == r3 {
-            // We didn't move, solidify!
-            rock.solidify(&mut grid);
-            if rocks_count == 2022 {
-                break 'lp;
+        rock = match rock.mv(Direction::Down, &grid) {
+            Ok(rr) => rr, // Complete the move!
+            Err(rr) => {
+                // We didn't move, solidify!
+                rr.solidify(&mut grid);
+                if rocks_count == 2022 {
+                    break 'lp;
+                }
+                // Measure height...
+                let max_rock = rock_height(&grid);
+                // Extend grid to max_rock + 7 (enough room for any new rocks at a height of at least 3 over the old ones)
+                let ext = (max_rock+7)-grid.len();
+                if ext > 0 {
+                    grid.extend((0..ext).map(|_| { (0..width).map(|_| { AIR }).collect() }));
+                }
+                // remember how many rocks we did
+                rocks_count += 1;
+                // Spawn new rock
+                Rock {
+                    rtype: rocks.next().unwrap(),
+                    pos: Pos{x: 2, y: max_rock as i32 +3 }
+                }
             }
-            // Measure height...
-            let max_rock = rock_height(&grid);
-            // Extend grid to max_rock + 7 (enough room for any new rocks)
-            grid.extend((0..(max_rock+7)).map(|_| { (0..width).map(|_| { AIR }).collect() }));
-            // Spawn new rock
-            rock = Rock {
-                rtype: rocks.next().unwrap(),
-                pos: Pos{x: 2, y: 3}
-            };
-            // remember how many rocks we did
-            rocks_count += 1;
-        } else {
-            rock = r3;
-        }
+        };
+        //print(&grid, &rock, rocks_count);
+        //sleep(Duration::from_millis(100));
     }
     println!("Day 17: {}", rock_height(&grid));
 }
\ No newline at end of file
diff --git a/src/main.rs b/src/main.rs
index 34d8bad..a40ab53 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -37,5 +37,5 @@ fn main() {
     // day14::run(fs::read_to_string("input/day14.txt").expect("Failed to read input file!"));
     // day15::run(fs::read_to_string("input/day15.txt").expect("Failed to read input file!"));
     // day16::run(fs::read_to_string("input/day16.txt").expect("Failed to read input file!"));
-    day17::run(fs::read_to_string("input/day17_ex.txt").expect("Failed to read input file!"));
+    day17::run(fs::read_to_string("input/day17.txt").expect("Failed to read input file!"));
 }