make nodes depend on snake length

battlesnake/src/logic.rs

@@ -19,7 +19,7 @@ use std::{
 
 use log::{error, info, warn};
 use ordered_float::OrderedFloat;
-use rand::thread_rng;
+use rand::{prelude::*, thread_rng};
 use serde_json::{json, Value};
 
 use crate::{
@@ -172,7 +172,8 @@ pub fn get_move(
     let chosen = actions
         .iter()
         .max_by_key(|(_, stat)| OrderedFloat(stat.won as f64 / stat.played as f64))
-        .map(|(direction, _)| *direction)?;
+        .map(|(direction, _)| *direction)
+        .or_else(|| possible_actions.iter().choose(&mut thread_rng()).copied())?;
 
     info!(
         "DIRECTION {turn}: {chosen:?} after {}ms ({})",
@@ -205,7 +206,7 @@ struct DeadlineError;
 struct Node {
     statistic: Statistics,
     child_statistics: BTreeMap<SnakeToken, BTreeMap<Direction, ActionStatistic>>,
-    childs: BTreeMap<BTreeMap<SnakeToken, Direction>, Node>,
+    childs: BTreeMap<BTreeMap<SnakeToken, (Direction, usize)>, Node>,
 }
 
 impl Node {
@@ -258,9 +259,13 @@ impl Node {
                 .collect();
 
             board.simulate_actions(&actions, &mut thread_rng());
+            let map_actions = actions
+                .iter()
+                .map(|(&snake, &action)| (snake, (action, board.snake_length(snake).unwrap_or(0))))
+                .collect();
             let winner = self
                 .childs
-                .entry(actions.clone())
+                .entry(map_actions)
                 .or_default()
                 .monte_carlo_step(board, deadline)?;
 
@@ -352,9 +357,13 @@ impl Node {
                 return Err(DeadlineError);
             }
             board.simulate_actions(&actions, &mut thread_rng());
+            let map_actions = actions
+                .iter()
+                .map(|(&snake, &action)| (snake, (action, board.snake_length(snake).unwrap_or(0))))
+                .collect();
             let lengths = self
                 .childs
-                .entry(actions.clone())
+                .entry(map_actions)
                 .or_default()
                 .monte_carlo_step_solo(board, deadline)?;
 

battlesnake/src/main.rs

@@ -1,6 +1,6 @@
 #![allow(clippy::needless_pass_by_value)]
 
-use battlesnake::{logic, Action, GameState};
+use battlesnake::{logic, Action, Direction, GameState};
 use log::{error, info};
 use rocket::{
     fairing::AdHoc, get, http::Status, launch, post, routes, serde::json::Json, tokio::task,
@@ -26,7 +26,7 @@ fn handle_start(start_req: Json<GameState>) -> Status {
 }
 
 #[post("/move", format = "json", data = "<move_req>")]
-async fn handle_move(move_req: Json<GameState>) -> Option<Json<Action>> {
+async fn handle_move(move_req: Json<GameState>) -> Json<Action> {
     let start = Instant::now();
     let response = task::spawn_blocking(move || {
         logic::get_move(
@@ -40,9 +40,13 @@ async fn handle_move(move_req: Json<GameState>) -> Option<Json<Action>> {
     .await
     .inspect_err(|e| error!("failed to join compute thread: {e}"))
     .ok()
-    .flatten()?;
+    .flatten()
+    .unwrap_or(Action {
+        r#move: Direction::Up,
+        shout: Some("I am so dead".to_owned()),
+    });
 
-    Some(Json(response))
+    Json(response)
 }
 
 #[post("/end", format = "json", data = "<end_req>")]