From f1c397b850edc48ea762bdb1a2bcce2d7316e38e Mon Sep 17 00:00:00 2001
From: "github-classroom[bot]"
 <66690702+github-classroom[bot]@users.noreply.github.com>
Date: Sat, 25 Oct 2025 14:04:47 +0000
Subject: [PATCH 1/3] add deadline

---
 README.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/README.md b/README.md
index 8adb718..505e227 100644
--- a/README.md
+++ b/README.md
@@ -1,3 +1,4 @@
+[![Review Assignment Due Date](https://classroom.github.com/assets/deadline-readme-button-22041afd0340ce965d47ae6ef1cefeee28c7c493a6346c4f15d667ab976d596c.svg)](https://classroom.github.com/a/FN98O3k7)
 ## Environment setup (Python 3.10+ recommended)
 - Clone repo
 - Open VSCode and go to the program folder

From 077203826c8c01ecae0a41434e05e8ab1fe0d3cb Mon Sep 17 00:00:00 2001
From: Adam R <adam@rosenblatt.ca>
Date: Sat, 25 Oct 2025 13:36:30 -0400
Subject: [PATCH 2/3] alpha beta pruning implemented

---
 homemade.py | 22 ++++++++++++++++++----
 1 file changed, 18 insertions(+), 4 deletions(-)

diff --git a/homemade.py b/homemade.py
index 8d7f558..97fab05 100644
--- a/homemade.py
+++ b/homemade.py
@@ -180,7 +180,7 @@ def evaluate(b: chess.Board) -> int:
             return score
 
         # --- plain minimax (no alpha-beta) ---
-        def minimax(b: chess.Board, depth: int, maximizing: bool) -> int:
+        def minimax(b: chess.Board, depth: int, maximizing: bool, alpha, beta) -> int:
             if depth == 0 or b.is_game_over():
                 return evaluate(b)
 
@@ -188,19 +188,33 @@ def minimax(b: chess.Board, depth: int, maximizing: bool) -> int:
                 best = -10**12
                 for m in b.legal_moves:
                     b.push(m)
-                    val = minimax(b, depth - 1, False)
+                    val = minimax(b, depth - 1, False, alpha, beta)
                     b.pop()
                     if val > best:
                         best = val
+                    
+                    if best > alpha:
+                        alpha = best
+
+                    if beta <= alpha:
+                        break
+
                 return best
             else:
                 best = 10**12
                 for m in b.legal_moves:
                     b.push(m)
-                    val = minimax(b, depth - 1, True)
+                    val = minimax(b, depth - 1, True, alpha, beta)
                     b.pop()
                     if val < best:
                         best = val
+
+                    if best < beta:
+                        beta = best
+
+                    if beta >= alpha:
+                        break
+
                 return best
 
         # --- root move selection ---
@@ -216,7 +230,7 @@ def minimax(b: chess.Board, depth: int, maximizing: bool) -> int:
         # Lookahead depth chosen by the simple time heuristic; subtract one for the root move
         for m in legal:
             board.push(m)
-            val = minimax(board, total_depth - 1, not maximizing)
+            val = minimax(board, total_depth - 1, not maximizing, -10**12, 10**12)
             board.pop()
 
             if maximizing and val > best_eval:

From a6a9426264b976254fe9c106975f50ca4db37910 Mon Sep 17 00:00:00 2001
From: Adam R <adam@rosenblatt.ca>
Date: Sat, 25 Oct 2025 13:44:34 -0400
Subject: [PATCH 3/3] fixed alpha beta pruning condition

---
 homemade.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/homemade.py b/homemade.py
index 97fab05..2ef2e9b 100644
--- a/homemade.py
+++ b/homemade.py
@@ -212,7 +212,7 @@ def minimax(b: chess.Board, depth: int, maximizing: bool, alpha, beta) -> int:
                     if best < beta:
                         beta = best
 
-                    if beta >= alpha:
+                    if beta <= alpha:
                         break
 
                 return best