From b8a63495257156830043f112716aeb52104e5d13 Mon Sep 17 00:00:00 2001
From: Simon Gardling <titaniumtown@proton.me>
Date: Sun, 9 Feb 2025 02:39:42 -0500
Subject: [PATCH] fix

---
 Cargo.toml          |  4 +--
 src/complexagent.rs | 76 +++++++++++++++++++--------------------------
 2 files changed, 34 insertions(+), 46 deletions(-)

diff --git a/Cargo.toml b/Cargo.toml
index 187fb90..2d375f3 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -5,5 +5,5 @@ edition = "2021"
 
 [dependencies]
 num = "0.4"
-rand = "0.9.0"
-rayon = "1.10.0"
+rand = "0.9"
+rayon = "1.10"
diff --git a/src/complexagent.rs b/src/complexagent.rs
index 7de4f00..69737b9 100644
--- a/src/complexagent.rs
+++ b/src/complexagent.rs
@@ -55,20 +55,22 @@ impl FutureMoves {
         let mut layers: Vec<Vec<Move>> = Vec::with_capacity(depth);
         layers.push(prob_space_idx(board, color, None).collect());
 
-        layers.extend(
-            (0..depth)
-                .flat_map(|i| layers.get(i))
-                .map(|layers_at_depth| {
-                    layers_at_depth
-                        .iter()
-                        .enumerate()
-                        .flat_map(|(parent_idx, parent_move)| {
-                            prob_space_idx(&parent_move.board, !parent_move.color, Some(parent_idx))
-                        })
-                        .collect::<Vec<_>>()
-                })
-                .collect::<Vec<_>>(),
-        );
+        for current_depth in 0..depth {
+            let current_layer = &layers[current_depth];
+            if current_layer.is_empty() {
+                break;
+            }
+
+            layers.push(
+                current_layer
+                    .iter()
+                    .enumerate()
+                    .flat_map(|(parent_idx, parent_move)| {
+                        prob_space_idx(&parent_move.board, !parent_move.color, Some(parent_idx))
+                    })
+                    .collect(),
+            );
+        }
 
         let mut tmp = Self {
             inner: layers,
@@ -79,29 +81,22 @@ impl FutureMoves {
     }
 
     fn compute_values(&mut self) {
-        let layers_len = self.inner.len();
-        for depth in (0..layers_len).rev() {
-            let layer_depth_1: Vec<Move> = if depth + 1 < layers_len {
-                self.inner[depth + 1].clone()
-            } else {
-                Vec::new()
-            };
+        // could be overhauled via this: https://github.com/rust-lang/rust/issues/75027
+        for depth in (0..self.inner.len()).rev() {
+            let (curr, prev) = self.inner.split_at_mut(depth + 1);
+            let curr = curr.last_mut().unwrap();
+            let prev = prev.first_mut().map(|x| x.as_slice()).unwrap_or(&[]);
 
-            let current_layer = &mut self.inner[depth];
-
-            current_layer.iter_mut().for_each(|mv| {
+            curr.iter_mut().for_each(|mv| {
                 let self_value = mv.compute_self_value(self.color, depth + 1);
-                let children_value = if depth + 1 < layers_len {
-                    // calculate average value of each move
-                    layer_depth_1
-                        .iter()
-                        .filter(|child| child.parent_index == Some(mv.parent_index.unwrap_or(0)))
-                        .map(|child| child.value)
-                        .sum::<i64>()
-                        / layer_depth_1.len() as i64
-                } else {
-                    0
-                };
+                // calculate average value of each move
+                let children_value = prev
+                    .iter()
+                    .filter(|child| child.parent_index == Some(mv.parent_index.unwrap_or(0)))
+                    .map(|child| child.value)
+                    .sum::<i64>()
+                    .checked_div(prev.len() as i64)
+                    .unwrap_or(0);
                 mv.value = self_value + children_value;
             });
         }
@@ -114,26 +109,19 @@ impl FutureMoves {
 
 pub struct ComplexAgent {
     color: Piece,
-    future_moves: Option<FutureMoves>,
 }
 
 impl ComplexAgent {
     #[allow(dead_code)]
     pub const fn new(color: Piece) -> Self {
-        Self {
-            color,
-            future_moves: None,
-        }
+        Self { color }
     }
 }
 
 impl Agent for ComplexAgent {
     fn next_move(&mut self, board: &Board) -> Option<(usize, usize)> {
         const LOOPS: usize = 5;
-        let layers = self
-            .future_moves
-            .take()
-            .unwrap_or_else(|| FutureMoves::generate(self.color, board, LOOPS));
+        let layers = FutureMoves::generate(self.color, board, LOOPS);
 
         println!(
             "# of moves {} deep: {}",