From 6a338182389a8847615d71dd8d51275df144a64e Mon Sep 17 00:00:00 2001
From: David Kruger <david@krugerlabs.us>
Date: Fri, 27 Jun 2025 16:07:33 -0700
Subject: [PATCH] We propagate the reward for both sides

The AI now properly choses the optimal path for the active player
---
 src/policy/backprop/mod.rs | 39 +++++++++++++++-----------------------
 1 file changed, 15 insertions(+), 24 deletions(-)

diff --git a/src/policy/backprop/mod.rs b/src/policy/backprop/mod.rs
index 1c98a14..7980461 100644
--- a/src/policy/backprop/mod.rs
+++ b/src/policy/backprop/mod.rs
@@ -69,18 +69,14 @@ fn standard_backprop<S: GameState>(
     let mut current_id: usize = node_id;
     loop {
         let node = arena.get_node_mut(current_id);
-        let player = node.state.get_current_player().clone();
-        match rewards.get(&player) {
-            Some(reward) => {
-                node.increment_visits();
-                node.record_player_reward(player, *reward);
-                if let Some(parent_id) = node.parent {
-                    current_id = parent_id;
-                } else {
-                    break;
-                }
-            }
-            None => (),
+        node.increment_visits();
+        for (player, reward) in rewards.iter() {
+            node.record_player_reward(player.clone(), *reward);
+        }
+        if let Some(parent_id) = node.parent {
+            current_id = parent_id;
+        } else {
+            break;
         }
     }
 }
@@ -94,19 +90,14 @@ fn weighted_backprop<S: GameState>(
     let mut current_id: usize = node_id;
     loop {
         let node = arena.get_node_mut(current_id);
-        let player = node.state.get_current_player().clone();
         let weight = weight_for_depth(depth_factor, node.depth);
-        match rewards.get(&player) {
-            Some(reward) => {
-                node.increment_visits();
-                node.record_player_reward(player, (*reward) * weight);
-                if let Some(parent_id) = node.parent {
-                    current_id = parent_id;
-                } else {
-                    break;
-                }
-            }
-            None => (),
+        for (player, reward) in rewards.iter() {
+            node.record_player_reward(player.clone(), (*reward) * weight);
+        }
+        if let Some(parent_id) = node.parent {
+            current_id = parent_id;
+        } else {
+            break;
         }
     }
 }