.

packages/solver-r/src/grid.rs

@@ -48,11 +48,15 @@ impl Grid {
     }
 }
 
+pub const DIRECTION_RIGHT: Point = Point { x: 1, y: 0 };
+pub const DIRECTION_LEFT: Point = Point { x: -1, y: 0 };
+pub const DIRECTION_UP: Point = Point { x: 0, y: 1 };
+pub const DIRECTION_DOWN: Point = Point { x: 0, y: -1 };
 pub const DIRECTIONS: [Point; 4] = [
-    Point { x: 1, y: 0 },
-    Point { x: -1, y: 0 },
-    Point { x: 0, y: 1 },
-    Point { x: 0, y: -1 },
+    DIRECTION_RIGHT,
+    DIRECTION_LEFT,
+    DIRECTION_UP,
+    DIRECTION_DOWN,
 ];
 
 #[test]

packages/solver-r/src/lib.rs

@@ -1,5 +1,6 @@
 mod grid;
 mod snake;
+mod snake_compact;
 mod snake_walk;
 mod solver;
 

packages/solver-r/src/snake-compact.rs

@@ -1,59 +0,0 @@
-use crate::grid::Point;
-
-#[derive(Copy, Clone, Debug, PartialEq, PartialOrd)]
-pub enum Direction {
-    Left = 0,
-    Right = 1,
-    Up = 2,
-    Down = 3,
-}
-
-fn get_direction_vector(dir: &Direction) -> Point {
-    match dir {
-        Direction::Down => Point { x: 0, y: -1 },
-        Direction::Up => Point { x: 0, y: 1 },
-        Direction::Left => Point { x: -1, y: 0 },
-        Direction::Right => Point { x: 1, y: 0 },
-    }
-}
-
-#[derive(Clone)]
-pub struct SnakeC {
-    pub head: Point,
-    pub body: Vec<Direction>,
-}
-impl SnakeC {
-    pub fn get_cells(&self) -> Vec<Point> {
-        let mut e = self.head.clone();
-        let mut out = Vec::new();
-
-        out.push(e.clone());
-        for dir in self.body.iter() {
-            let v = get_direction_vector(dir);
-            e.x -= v.x;
-            e.y -= v.y;
-            out.push(e.clone());
-        }
-
-        out
-    }
-}
-
-#[test]
-fn it_should_get_the_snake_cell() {
-    let s = SnakeC {
-        head: Point { x: 10, y: 5 },
-        body: vec![Direction::Up, Direction::Up, Direction::Left],
-    };
-
-    assert_eq!(
-        s.get_cells(),
-        vec![
-            //
-            Point { x: 10, y: 5 },
-            Point { x: 10, y: 4 },
-            Point { x: 10, y: 3 },
-            Point { x: 11, y: 3 },
-        ]
-    );
-}

packages/solver-r/src/snake.rs

@@ -1,6 +1,64 @@
-use crate::grid::Point;
+use crate::grid::{Point, DIRECTIONS, DIRECTION_DOWN, DIRECTION_LEFT, DIRECTION_UP};
 
 /**
 *  head is at 0
 */
 pub type Snake = Vec<Point>;
+
+pub fn move_snake(s: &mut Snake, dir: &Point) -> () {
+    let mut e = s.pop().unwrap();
+    e.x = s[0].x + dir.x;
+    e.y = s[0].y + dir.y;
+    s.insert(0, e);
+}
+pub fn will_self_collide(s: &Snake, dir: &Point) -> bool {
+    let next_head = Point {
+        x: s[0].x + dir.x,
+        y: s[0].y + dir.y,
+    };
+
+    (&s[0..(s.len() - 1)]).contains(&next_head)
+}
+
+#[test]
+fn it_should_detect_self_collide() {
+    let mut s = vec![
+        //
+        Point { x: 6, y: 0 },
+        Point { x: 5, y: 0 },
+        Point { x: 4, y: 0 },
+        Point { x: 3, y: 0 },
+        Point { x: 2, y: 0 },
+        Point { x: 1, y: 0 },
+    ];
+
+    move_snake(&mut s, &DIRECTION_UP);
+    move_snake(&mut s, &DIRECTION_LEFT);
+
+    assert_eq!(will_self_collide(&s, &DIRECTION_DOWN), true);
+
+    move_snake(&mut s, &DIRECTION_LEFT);
+
+    assert_eq!(will_self_collide(&s, &DIRECTION_DOWN), false);
+}
+#[test]
+fn it_should_move_snake() {
+    let mut s = vec![
+        //
+        Point { x: 3, y: 0 },
+        Point { x: 2, y: 0 },
+        Point { x: 1, y: 0 },
+    ];
+
+    move_snake(&mut s, &DIRECTION_UP);
+
+    assert_eq!(
+        s,
+        vec![
+            //
+            Point { x: 3, y: 1 },
+            Point { x: 3, y: 0 },
+            Point { x: 2, y: 0 },
+        ]
+    );
+}

packages/solver-r/src/snake_walk.rs

@@ -9,6 +9,13 @@ pub fn get_route_to_eat_all(
     initial_snake: &Snake,
     cells_to_eat: HashSet<Point>,
 ) -> Vec<Snake> {
+    let mut targets = cells_to_eat.clone();
+
+    while let Some(p) = targets.iter().next().cloned() {
+        targets.remove(&p);
+
+        let mut open_list: HashSet<Snake> = HashSet::new();
+    }
     for dir in DIRECTIONS {}
     Vec::new()
 }