Day 10 part 2

day10/src/main.rs

@@ -60,19 +60,24 @@ impl TryFrom<char> for Tile {
     }
 }
 
+impl Tile {
+    fn char(&self) -> char {
+        match (self.n, self.e, self.s, self.w) {
+            (false, true, false, true) => '-',
+            (true, false, true, false) => '|',
+            (true, true, false, false) => 'L',
+            (true, false, false, true) => 'J',
+            (false, false, true, true) => '7',
+            (false, true, true, false) => 'F',
+            (false, false, false, false) => '.',
+           _ => '?',
+       }     
+    }
+}
+
 impl Display for Tile {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        let c = match (self.n, self.e, self.s, self.w) {
+        write!(f, "{}", self.char())
-             (false, true, false, true) => '-',
-             (true, false, true, false) => '|',
-             (true, true, false, false) => 'L',
-             (true, false, false, true) => 'J',
-             (false, false, true, true) => '7',
-             (false, true, true, false) => 'F',
-             (false, false, false, false) => '.',
-            _ => '?',
-        };
-        write!(f, "{}", c)
     }
 }
 
@@ -131,7 +136,21 @@ impl Map {
         Self { grid, start: self.start }
     }
 
-    fn fill
+    fn fill(&self) -> Matrix<bool> {
+        let shape = self.grid.shape();
+        let mut map = Matrix::constant(false, (shape.0 + 1, shape.1 + 1));
+
+        for x in 1..shape.0 {
+            for y in 1..shape.1 {
+                let cell = &self.grid[x-1][y-1];
+                map[x][y] = map[x-1][y-1] ^ cell.n ^ cell.e;
+            }
+        }
+
+        map
+    }
+
+    
 
 }
 
@@ -208,5 +227,29 @@ fn main() -> Result<()> {
         .find_map(|(c, (a,b))| Some(c+1).filter(|_| a == b)).unwrap();
 
     println!("Collide at {len}");
+
+    let fillmap = map.fill();
+
+    let mut filled = Matrix::constant('?', map.grid.shape());
+    for (x,y) in filled.indices() {
+        let p: Tile = map.grid[x][y];
+        let f = fillmap[x][y];
+
+        filled[x][y] = if !(p.n || p.e || p.s || p.w) {
+            if f { 'I' } else { 'O' }
+        } else {
+            p.char()
+        }
+    }
+
+    println!("Filled:\n{}", filled);
+
+    let surface = filled.elems()
+        .copied()
+        .filter(|&e| e == 'I')
+        .count();
+
+    println!("Inner surface: {surface}");
+
     Ok(())
 }

myutils/src/matrix.rs

@@ -1,7 +1,7 @@
 //! A large number of logical games, by virtue of existing on paper, use 2-dimensional structures.
 //! This module implement packed matrices, without the overhead of supporting multiple dimensions.
 
-use std::ops::{Index, IndexMut};
+use std::{ops::{Index, IndexMut}, fmt::Display};
 
 use thiserror::Error;
 
@@ -57,6 +57,10 @@ impl <T> Matrix<T> {
         (0..h).flat_map(move |x| (0..w).map(move |y| (x,y)))
     }
 
+    pub fn elems(&self) -> impl Iterator<Item=&T> {
+        self.vec.iter()
+    }
+
     /// Lists all the neighbors of the given location, truncating at the edge.
     pub fn neighbors(&self, pos: (usize, usize)) -> Vec<(usize,usize)> {
         let (x,y) = pos;
@@ -92,6 +96,25 @@ impl <T> Matrix<T> {
 
 }
 
+impl <T: Clone> Matrix<T> {
+    pub fn constant(item: T, shape: (usize, usize)) -> Self {
+        let data = vec![item; shape.0 * shape.1];
+        Matrix::new(data, shape).unwrap()
+    }
+}
+
+impl <T: Display> Display for Matrix<T> {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        for l in self.lines() {
+            for e in l {
+                write!(f, "{}", e)?;
+            }
+            writeln!(f)?;
+        }
+        Ok(())
+    }
+}
+
 impl <T> Index<usize> for Matrix<T> {
     type Output = [T];
 
@@ -109,7 +132,7 @@ impl <T> IndexMut<usize> for Matrix<T> {
 
 macro_rules! umat {
     [$e:expr; $shape:expr] => {
-        $crate::util::matrix::Matrix::new(vec![$e; $shape.0 * $shape.1], $shape).unwrap()
+        $crate::matrix::Matrix::new(vec![$e; $shape.0 * $shape.1], $shape).unwrap()
     };
 }
 pub(crate) use umat;
@@ -134,7 +157,7 @@ pub(crate) use mat;
 
 #[cfg(test)]
 mod test {
-    use crate::util::matrix::ShapeError;
+    use crate::matrix::ShapeError;
 
     use super::Matrix;