battlesnake/src/logic.rs

@@ -10,12 +10,11 @@
 // To get you started we've included code to prevent your Battlesnake from moving backwards.
 // For more info see docs.battlesnake.com
 
-use std::{cmp::Ordering, time::Instant};
-
 use log::info;
+use rand::seq::SliceRandom;
 use serde_json::{json, Value};
 
-use crate::{simulation, Action, Battlesnake, Board, Direction, Game, MAX_HEALTH};
+use crate::{Action, Battlesnake, Board, Direction, Game, MAX_HEALTH};
 
 impl Battlesnake {
     fn possible_actions_without_heads<'a>(
@@ -110,72 +109,17 @@ 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) -> Option<Action> {
-    let id_map = board
+    let actions = you.possible_actions(game, board);
-        .snakes
+    if actions.is_empty() {
-        .iter()
+        return None;
-        .enumerate()
+    }
-        .map(|(i, snake)| (snake.id.clone(), u8::try_from(i).unwrap()))
-        .collect();
-    let board = simulation::Board::from_game_board(board, &id_map, turn);
 
-    let my_id = id_map[&you.id];
+    // Choose a random move from the safe ones
-    let my_index = board.snake_index(my_id)?;
+    let chosen = actions.choose(&mut rand::thread_rng())?;
-
-    let possible_actions = board.possible_actions();
-
-    let my_actions = &possible_actions[my_index];
-
-    let actions = my_actions
-        .iter()
-        .map(|direction| {
-            let mut actions = vec![None; possible_actions.len()];
-            actions[my_index] = Some(*direction);
-            let mut wins = 0;
-            let mut total_turns = 0;
-            let start = Instant::now();
-            for _ in 0..100 {
-                let mut board = board.clone();
-                board.simulate_with_initial_until(&actions[..], |board| {
-                    !board.is_alive(my_id)
-                        || (game.ruleset.name != "solo" && board.alive_snakes() <= 1)
-                });
-                if board.is_alive(my_id) {
-                    // we survived
-                    wins += 2;
-                } else if board.alive_snakes() == 0 {
-                    // no snake is alive. This is a draw
-                    wins += 1;
-                } else {
-                    // we lost
-                    wins += 0;
-                }
-                total_turns += board.turn();
-            }
-            let end = Instant::now();
-            info!(
-                "Simulation for {direction:?} took {}s",
-                (end - start).as_secs_f32()
-            );
-
-            (direction, wins, total_turns)
-        })
-        .collect::<Vec<_>>();
-
-    info!("actions: {actions:?}");
-
-    let (&chosen, _, _) =
-        actions
-            .into_iter()
-            .max_by(
-                |(_, score1, turns1), (_, score2, turns2)| match score1.cmp(score2) {
-                    Ordering::Equal => turns1.cmp(turns2),
-                    order => order,
-                },
-            )?;
 
     info!("DIRECTION {}: {:?}", turn, chosen);
     Some(Action {
-        r#move: chosen,
+        r#move: *chosen,
         shout: None,
     })
 }

battlesnake/src/main.rs

@@ -11,7 +11,6 @@ use serde_json::Value;
 use std::env;
 
 mod logic;
-mod simulation;
 
 const MAX_HEALTH: i32 = 100;
 
@@ -120,7 +119,7 @@ pub struct RulesetSquad {
     shared_length: bool,
 }
 
-#[derive(Deserialize, Serialize, Debug, Clone)]
+#[derive(Deserialize, Serialize, Debug)]
 pub struct Board {
     /// The number of rows in the y-axis of the game board.
     height: i32,
@@ -135,7 +134,7 @@ pub struct Board {
     hazards: Vec<Coord>,
 }
 
-#[derive(Deserialize, Serialize, Debug, Clone)]
+#[derive(Deserialize, Serialize, Debug)]
 pub struct Battlesnake {
     /// Unique identifier for this Battlesnake in the context of the current Game
     id: String,

battlesnake/src/simulation.rs

@@ -1,257 +0,0 @@
-use std::collections::{BTreeSet, HashMap, VecDeque};
-
-use rand::seq::SliceRandom;
-
-use crate::{Coord, Direction};
-
-const MAX_HEALTH: u8 = crate::MAX_HEALTH as u8;
-
-#[derive(Debug, PartialEq, Eq, Clone)]
-pub struct Board {
-    turn: i32,
-    /// Height of the board
-    height: i32,
-    /// Width of the board
-    width: i32,
-    /// Food on the board
-    food: BTreeSet<Coord>,
-    /// Alive snakes
-    snakes: Vec<Battlesnake>,
-}
-
-impl Board {
-    pub fn from_game_board(board: &crate::Board, id_map: &HashMap<String, u8>, turn: i32) -> Self {
-        let width = board.width;
-        debug_assert!(width > 0);
-        let height = board.height;
-        debug_assert!(height > 0);
-        let food = board.food.iter().copied().collect();
-        let snakes = board
-            .snakes
-            .iter()
-            .map(|snake| {
-                let id = id_map[&snake.id];
-                Battlesnake::from_game_snake(snake, id)
-            })
-            .collect();
-
-        Self {
-            turn,
-            height,
-            width,
-            food,
-            snakes,
-        }
-    }
-
-    pub const fn turn(&self) -> i32 {
-        self.turn
-    }
-
-    pub fn snake_index(&self, id: u8) -> Option<usize> {
-        self.snakes
-            .iter()
-            .enumerate()
-            .find(|(_, snake)| snake.id == id)
-            .map(|(i, _)| i)
-    }
-
-    pub fn is_alive(&self, id: u8) -> bool {
-        self.snakes.iter().any(|snake| snake.id == id)
-    }
-
-    pub fn alive_snakes(&self) -> usize {
-        self.snakes.len()
-    }
-
-    pub fn simulate_actions(&mut self, actions: &[Direction]) {
-        debug_assert_eq!(self.snakes.len(), actions.len());
-
-        // move snakes
-        for (snake, direction) in self.snakes.iter_mut().zip(actions.iter()) {
-            snake.perform_action(*direction);
-        }
-
-        // feed snakes
-        for snake in &mut self.snakes {
-            let head = snake.head();
-            if self.food.remove(head) {
-                snake.health = MAX_HEALTH;
-            }
-        }
-
-        // kill snakes
-        let alive_ids = self
-            .snakes
-            .iter()
-            .filter(|snake| {
-                // snake must have enough health
-                snake.health != 0
-            })
-            .map(|snake| (snake.id, snake.body.len(), *snake.head()))
-            .filter(|(_, _, head)| {
-                // head in bounds
-                (0..self.width).contains(&head.x) && (0..self.height).contains(&head.y)
-            })
-            .filter(|(_, _, head)| {
-                // body collision
-                !self
-                    .snakes
-                    .iter()
-                    .flat_map(|snake2| snake2.body.iter().skip(1))
-                    .any(|body| body == head)
-            })
-            .filter(|(id, len, head)| {
-                // head to head collision
-                !self
-                    .snakes
-                    .iter()
-                    .filter(|snake2| snake2.id != *id && snake2.body.len() >= *len)
-                    .any(|snake2| snake2.head() == head)
-            })
-            .map(|(id, _, _)| id)
-            .collect::<Vec<_>>();
-        self.snakes.retain(|snake| alive_ids.contains(&snake.id));
-
-        self.turn += 1;
-    }
-
-    pub fn simulate_with_initial_until(
-        &mut self,
-        actions: &[Option<Direction>],
-        exit: impl Fn(&Self) -> bool,
-    ) {
-        debug_assert_eq!(actions.len(), self.snakes.len());
-        let possible_actions = self.possible_actions();
-        let actions = actions
-            .iter()
-            .enumerate()
-            .map(|(i, direction)| {
-                direction.unwrap_or_else(|| {
-                    possible_actions[i]
-                        .choose(&mut rand::thread_rng())
-                        .copied()
-                        .unwrap_or(Direction::Up)
-                })
-            })
-            .collect::<Vec<_>>();
-
-        self.simulate_actions(&actions);
-        while !exit(self) {
-            let actions = self
-                .possible_actions()
-                .iter()
-                .map(|actions| {
-                    actions
-                        .choose(&mut rand::thread_rng())
-                        .copied()
-                        .unwrap_or(Direction::Up)
-                })
-                .collect::<Vec<_>>();
-            self.simulate_actions(&actions);
-        }
-    }
-
-    pub fn possible_actions(&self) -> Vec<Vec<Direction>> {
-        let possible_actions = self
-            .snakes
-            .iter()
-            .map(|snake| {
-                enum_iterator::all::<Direction>()
-                    .map(|direction| (direction, snake.head().move_to(direction)))
-                    .filter(|(_, target)| {
-                        // don't move out of bounds
-                        (0..self.width).contains(&target.x) && (0..self.height).contains(&target.y)
-                    })
-                    .filter(|(_, target)| {
-                        // don't collide with other snakes
-                        !self
-                            .snakes
-                            .iter()
-                            .flat_map(|snake| {
-                                let has_eaten = snake.health == MAX_HEALTH;
-                                snake
-                                    .body
-                                    .iter()
-                                    .take(snake.body.len() - usize::from(!has_eaten))
-                            })
-                            .any(|coord| coord == target)
-                    })
-                    .map(|(direction, _)| direction)
-                    .collect::<Vec<_>>()
-            })
-            .collect::<Vec<_>>();
-
-        // don't move into bigger snakes heads with only one movement option
-        possible_actions
-            .iter()
-            .enumerate()
-            .map(|(i, actions)| {
-                let snake = &self.snakes[i];
-                let length = snake.body.len();
-                let head = snake.head();
-                actions
-                    .iter()
-                    .copied()
-                    .filter(|direction| {
-                        let target = head.move_to(*direction);
-                        !self
-                            .snakes
-                            .iter()
-                            .enumerate()
-                            .filter(|(_, snake)| {
-                                // only snakes that are longer
-                                snake.body.len() > length
-                            })
-                            .filter_map(|(i, snake)| match &possible_actions[i][..] {
-                                // only snakes that have a single action option
-                                [direction] => Some(snake.head().move_to(*direction)),
-                                _ => None,
-                            })
-                            .any(|coord| coord == target)
-                    })
-                    .collect()
-            })
-            .collect()
-    }
-}
-
-#[derive(Debug, PartialEq, Eq, Clone)]
-pub struct Battlesnake {
-    /// Id of the snake. Unique inside a game
-    id: u8,
-    /// health points
-    health: u8,
-    /// Body of the snake. The head is the first element in the queue
-    body: VecDeque<Coord>,
-}
-
-impl Battlesnake {
-    pub fn from_game_snake(snake: &crate::Battlesnake, id: u8) -> Self {
-        let body: VecDeque<_> = snake.body.iter().copied().collect();
-        debug_assert_eq!(body.len(), usize::try_from(snake.length).unwrap());
-        debug_assert!(snake.health <= crate::MAX_HEALTH);
-        let health = u8::try_from(snake.health).expect("max health is 100");
-        Self { id, health, body }
-    }
-
-    pub fn perform_action(&mut self, direction: Direction) {
-        debug_assert!(!self.body.is_empty());
-        // move the head along
-        self.body.push_front(self.head().move_to(direction));
-
-        // move tail
-        if self.health != MAX_HEALTH {
-            // only move the tail if we didn't eat
-            self.body.pop_back();
-        }
-
-        // decrease helth
-        self.health = self.health.saturating_sub(1);
-    }
-
-    pub fn head(&self) -> &Coord {
-        debug_assert!(!self.body.is_empty());
-        self.body.front().expect("not empty")
-    }
-}

xtask/src/main.rs

@@ -120,7 +120,6 @@ fn vs_production() -> Result<(), DynError> {
             "https://snake.mkaenner.de",
             "-g",
             "duel",
-            "--browser",
         ])
         .output();