move into unsafe directions as backup

battlesnake/src/logic.rs

@@ -58,6 +58,30 @@ impl Battlesnake {
 
         true
     }
+
+    #[must_use]
+    pub fn is_direction_death(&self, direction: Direction, game: &Game, board: &Board) -> bool {
+        let target = self.head.move_to(direction);
+
+        // check if target is out of bounds
+        if !((0..board.width).contains(&target.x) && (0..board.height).contains(&target.y)) {
+            return true;
+        }
+
+        // check if target is inside a snake
+        if board
+            .snakes
+            .iter()
+            .filter(|snake| {
+                !(game.ruleset.settings.squad.allow_body_collisions && self.squad == snake.squad)
+            })
+            .flat_map(|snake| snake.body.iter())
+            .any(|&coord| target == coord)
+        {
+            return true;
+        }
+        false
+    }
 }
 
 // info is called when you create your Battlesnake on play.battlesnake.com
@@ -89,13 +113,19 @@ pub fn end(_game: &Game, _turn: i32, _board: &Board, _you: &Battlesnake) {
 // Valid moves are "up", "down", "left", or "right"
 // See https://docs.battlesnake.com/api/example-move for available data
 pub fn get_move(game: &Game, turn: i32, board: &Board, you: &Battlesnake) -> Move {
-    let safe_moves = enum_iterator::all()
+    let moves = enum_iterator::all()
+        .filter(|&direction| !you.is_direction_death(direction, game, board))
+        .collect::<Vec<_>>();
+    let safe_moves = moves
+        .iter()
+        .copied()
         .filter(|&direction| you.is_direction_safe(direction, game, board))
         .collect::<Vec<_>>();
 
     // Choose a random move from the safe ones
     let chosen = safe_moves
         .choose(&mut rand::thread_rng())
+        .or_else(|| moves.choose(&mut rand::thread_rng()))
         .unwrap_or(&Direction::Up);
 
     info!("MOVE {}: {:?}", turn, chosen);