refactor: make is_end as function argument instead of struct property

Author: manhunto

src/solutions/year2023/day17.rs

@@ -68,14 +68,14 @@ impl Day17 {
         let cost = move |_, next: Node| {
             *grid_clone.get_for_point(&next.vector.position()).unwrap() as usize
         };
-        let dijkstra: Dijkstra<Node> = Dijkstra::new(adjacency, Box::new(cost), Box::new(is_end));
+        let dijkstra: Dijkstra<Node> = Dijkstra::new(adjacency, Box::new(cost));
 
         let starts = vec![
             Node::new(start_point, Direction::East),
             Node::new(start_point, Direction::South),
         ];
 
-        dijkstra.cost(starts).unwrap().to_string()
+        dijkstra.cost(starts, &is_end).unwrap().to_string()
     }
 
     fn filter_out_outside_grid(vec: Vec<Node>, grid: &Grid<u8>) -> Vec<Node> {

src/solutions/year2024/day16.rs

@@ -11,17 +11,19 @@ pub struct Day16;
 impl Solution for Day16 {
     fn part_one(&self, input: &str) -> String {
         let (grid, start, end) = Self::setup_grid(input);
-        let dijkstra = Self::create_dijkstra(grid, end);
+        let dijkstra = Self::create_dijkstra(grid);
+        let is_end = Self::is_end_closure(end);
 
-        dijkstra.cost(vec![start]).unwrap().to_string()
+        dijkstra.cost(vec![start], &is_end).unwrap().to_string()
     }
 
     fn part_two(&self, input: &str) -> String {
         let (grid, start, end) = Self::setup_grid(input);
-        let dijkstra = Self::create_dijkstra(grid, end);
+        let dijkstra = Self::create_dijkstra(grid);
+        let is_end = Self::is_end_closure(end);
 
         dijkstra
-            .all_paths(vec![start])
+            .all_paths(vec![start], &is_end)
             .iter()
             .flat_map(|path| path.iter().map(|p| p.position()))
             .unique()
@@ -40,12 +42,11 @@ impl Day16 {
         (grid, start, end)
     }
 
-    fn create_dijkstra(grid: Grid<char>, end: Point) -> Dijkstra<Vector> {
+    fn create_dijkstra(grid: Grid<char>) -> Dijkstra<Vector> {
         let adjacency = Self::adjacency_closure(grid);
         let cost = Self::cost_closure();
-        let is_end = Self::is_end_closure(end);
 
-        Dijkstra::new(adjacency, cost, is_end)
+        Dijkstra::new(adjacency, cost)
     }
 
     fn adjacency_closure(grid: Grid<char>) -> Box<dyn Fn(Vector) -> Vec<Vector>> {

src/solutions/year2024/day21.rs

@@ -1,7 +1,7 @@
 use crate::solutions::year2024::day21::Key::{Activate, Dir};
 use crate::solutions::Solution;
 use crate::utils::direction::Direction;
-use crate::utils::graphs::a_star::AStarBuilder;
+use crate::utils::graphs::dijkstra::Dijkstra;
 use crate::utils::grid::Grid;
 use crate::utils::point::Point;
 use itertools::Itertools;
@@ -53,38 +53,38 @@ impl Day21 {
             let path = self.path_for_str(&current, pad);
 
             current = path.iter().map(|key| key.to_string()).collect::<String>();
-
-            // println!("{}", current);
         }
 
         current.chars().count()
     }
 
     fn path_for_str(&self, code: &str, pad: &Pad) -> Vec<Key> {
         let code = "A".to_owned() + code;
+        let adjacent = pad.adjacent.clone();
 
-        let neighbours = |p: Point| pad.adjacent(&p);
-        let distance = |_, _| 1;
+        let neighbours = Box::new(move |p: Point| adjacent.get(&p).unwrap().to_vec());
+        let distance = Box::new(|_, _| 1);
 
-        let a_star = AStarBuilder::init(&neighbours, &distance).build();
+        let dijkstra = Dijkstra::new(neighbours, distance);
 
         code.chars()
             .tuple_windows()
             .flat_map(|(from, to)| {
-                let path = a_star
-                    .path(
-                        pad.position(from as u8).unwrap(),
-                        pad.position(to as u8).unwrap(),
-                    )
-                    .unwrap();
-                let mut directions: Vec<Key> = path
+                let start = pad.position(from as u8).unwrap();
+                let end = pad.position(to as u8).unwrap();
+
+                let is_end = |p: Point| p == end;
+                let path = dijkstra.all_paths(vec![start], &is_end);
+
+                let min_path = path.iter().min_by_key(|p| p.len()).unwrap();
+                let mut directions: Vec<Key> = min_path
+                    .iter()
+                    .collect_vec()
                     .windows(2)
-                    .map(|pair| Dir(pair[0].direction(&pair[1]).unwrap()))
+                    .map(|pair| Dir(pair[0].direction(pair[1]).unwrap()))
                     .collect();
                 directions.push(Activate);
 
-                // println!("{from} {to} -> {:?}", directions.iter().map(|d| d.to_string()).collect::<String>());
-
                 directions.into_iter()
             })
             .collect()
@@ -171,10 +171,6 @@ impl Pad {
     fn position(&self, element: u8) -> Option<Point> {
         self.positions.get(&element).copied()
     }
-
-    fn adjacent(&self, position: &Point) -> Vec<Point> {
-        self.adjacent.get(position).unwrap().to_vec()
-    }
 }
 
 #[cfg(test)]

src/utils/graphs/dijkstra.rs

@@ -7,23 +7,14 @@ use std::hash::Hash;
 pub struct Dijkstra<T> {
     neighbours: Box<dyn Fn(T) -> Vec<T>>,
     cost: Box<dyn Fn(T, T) -> usize>,
-    is_end: Box<dyn Fn(T) -> bool>,
 }
 
 impl<T> Dijkstra<T> {
-    pub fn new(
-        neighbours: Box<dyn Fn(T) -> Vec<T>>,
-        cost: Box<dyn Fn(T, T) -> usize>,
-        is_end: Box<dyn Fn(T) -> bool>,
-    ) -> Self {
-        Self {
-            neighbours,
-            cost,
-            is_end,
-        }
+    pub fn new(neighbours: Box<dyn Fn(T) -> Vec<T>>, cost: Box<dyn Fn(T, T) -> usize>) -> Self {
+        Self { neighbours, cost }
     }
 
-    pub fn cost(&self, starts: Vec<T>) -> Option<usize>
+    pub fn cost(&self, starts: Vec<T>, is_end: &dyn Fn(T) -> bool) -> Option<usize>
     where
         T: Hash + Eq + PartialEq + Ord + Copy + Debug,
     {
@@ -36,7 +27,7 @@ impl<T> Dijkstra<T> {
         }
 
         while let Some(State { cost, node }) = heap.pop() {
-            if (self.is_end)(node) {
+            if is_end(node) {
                 return Some(cost);
             }
 
@@ -56,7 +47,7 @@ impl<T> Dijkstra<T> {
 
     /// It returns every possible visited node
     /// Even if there is a many possible ways to reach end
-    pub fn all_paths(&self, starts: Vec<T>) -> Vec<VecDeque<T>>
+    pub fn all_paths(&self, starts: Vec<T>, is_end: &dyn Fn(T) -> bool) -> Vec<VecDeque<T>>
     where
         T: Hash + Eq + PartialEq + Ord + Debug + Copy,
     {
@@ -74,7 +65,7 @@ impl<T> Dijkstra<T> {
         let mut end_nodes: Vec<T> = Vec::new();
 
         while let Some(State { cost, node }) = heap.pop() {
-            if (self.is_end)(node) {
+            if is_end(node) {
                 lowest = Some(cost);
                 end_nodes.push(node);
 
@@ -171,10 +162,10 @@ mod test {
                 _ => unreachable!("Invalid node"),
             }),
             Box::new(|_: char, _: char| 1),
-            Box::new(|node: char| node == '<'),
         );
+        let is_end = |node: char| node == '<';
 
-        let paths = dijkstra.all_paths(vec!['A']);
+        let paths = dijkstra.all_paths(vec!['A'], &is_end);
 
         assert_eq!(paths.len(), 2);
         assert!(paths.contains(&VecDeque::from(vec!['A', '^', 'v', '<'])));