From 4e44ac548cf8a8a0b3c76befa30561657b27c5d3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Max=20K=C3=A4nner?= <max.kaenner@gmail.com>
Date: Sun, 6 Oct 2024 22:28:08 +0200
Subject: [PATCH] make nodes depend on snake length

---
 battlesnake/src/logic.rs | 19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)

diff --git a/battlesnake/src/logic.rs b/battlesnake/src/logic.rs
index 324f79c..89a73e0 100644
--- a/battlesnake/src/logic.rs
+++ b/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)?;