From 6b935296b7f29f59f584d97eff64f75251528b59 Mon Sep 17 00:00:00 2001
From: Mark Bluemer <bluemer.mark@gmail.com>
Date: Tue, 2 May 2017 11:54:13 -0400
Subject: [PATCH] fixed alpha beta

---
 src/MinimaxSearch.cpp | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/src/MinimaxSearch.cpp b/src/MinimaxSearch.cpp
index 0869ee2..9acaeff 100644
--- a/src/MinimaxSearch.cpp
+++ b/src/MinimaxSearch.cpp
@@ -40,21 +40,19 @@ double MinimaxSearch::alphaBeta(bup &board, double alpha, double beta, int depth
 //
   // black is max player here
   double v;
-  if (board->player() == "black") {
+  if (board->getIsBlacksTurn()) {
     v = std::numeric_limits<double>::lowest();
     for (mup &move : board->actions()) {
       bup result = board->result(move);
-      v = std::max(v, alphaBeta(result, alpha, beta, depth + 1));
-      if (v >= beta) return v;
-      alpha = std::max(alpha, v);
+      alpha = std::max(alpha, alphaBeta(result, alpha, beta, depth + 1));
+      if (beta <= alpha) return beta;
     }
   } else {
     v = std::numeric_limits<double>::max();
     for (mup &move : board->actions()) {
       bup result = board->result(move);
-      v = std::min(v, alphaBeta(result, alpha, beta, depth + 1));
-      if (v <= alpha) return v;
-      beta = std::min(beta, v);
+      beta = std::min(beta, alphaBeta(result, alpha, beta, depth + 1));
+      if (beta <= alpha) return alpha;
     }
   }