From c1957e7beebebad9c386c0cb88b3fffcea942d75 Mon Sep 17 00:00:00 2001
From: Calcitem <calcitem@outlook.com>
Date: Fri, 1 May 2020 01:19:04 +0800
Subject: [PATCH] =?UTF-8?q?ai:=20=E5=A2=9E=E5=8A=A0=E7=A9=BA=E7=9D=80?=
 =?UTF-8?q?=E5=90=91=E5=89=8D=E8=A3=81=E5=89=AA=E9=83=A8=E5=88=86=E4=BB=A3?=
 =?UTF-8?q?=E7=A0=81=20(=E6=9C=AA=E5=AE=8C=E6=88=90)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

宏未开启。
---
 include/config.h      |  2 ++
 src/ai/movegen.cpp    |  7 +++++++
 src/ai/search.cpp     | 26 ++++++++++++++++++++++++++
 src/ai/search.h       |  3 +++
 src/game/position.cpp | 12 ++++++++++++
 src/game/position.h   |  4 ++++
 6 files changed, 54 insertions(+)

diff --git a/include/config.h b/include/config.h
index 87f1373c..5db8f312 100644
--- a/include/config.h
+++ b/include/config.h
@@ -57,6 +57,8 @@
 #define DEPTH_ADJUST (0)
 //#define FIX_DEPTH   (24)
 
+//#define NULL_MOVE
+
 //#define FIRST_MOVE_STAR_PREFERRED
 
 //#define TIME_STAT
diff --git a/src/ai/movegen.cpp b/src/ai/movegen.cpp
index bbb8c27f..05507705 100644
--- a/src/ai/movegen.cpp
+++ b/src/ai/movegen.cpp
@@ -172,6 +172,13 @@ int StateInfo::generateMoves(Stack<move_t, MOVE_COUNT> &moves)
     return moves.size();
 }
 
+int StateInfo::generateNullMove(Stack<move_t, MOVE_COUNT> &moves)
+{
+    moves.clear();
+    moves.push_back((move_t)SQ_0);
+    return moves.size();
+}
+
 void MoveList::create()
 {
     // Note: 未严格按 direction_t 中枚举的顺序从左到右排列
diff --git a/src/ai/search.cpp b/src/ai/search.cpp
index 8a5df727..47b6a213 100644
--- a/src/ai/search.cpp
+++ b/src/ai/search.cpp
@@ -799,6 +799,20 @@ value_t AIAlgorithm::search(depth_t depth, value_t alpha, value_t beta, Node *no
         }
 #endif
 
+#ifdef NULL_MOVE
+        // 空着向前裁剪 (WIP)
+        doNullMove();
+        st->generateNullMove(moves);
+        st->generateChildren(moves, this, node);
+        value = -search(depth - 1 - 2, -beta, -beta + 1, node->children[0]);
+        undoNullMove();
+
+        if (value >= beta) {
+            node->value = beta;
+            return beta;
+        }
+#endif
+
 #ifdef TRANSPOSITION_TABLE_ENABLE
         // 记录确切的哈希值
         TT::recordHash(node->value,
@@ -963,6 +977,18 @@ void AIAlgorithm::undoMove()
     positionStack.pop();
 }
 
+void AIAlgorithm::doNullMove()
+{
+    // 执行空着
+    st->doNullMove();
+}
+
+void AIAlgorithm::undoNullMove()
+{
+    // 执行空着
+    st->undoNullMove();
+}
+
 #ifdef ALPHABETA_AI
 const char* AIAlgorithm::bestMove()
 {
diff --git a/src/ai/search.h b/src/ai/search.h
index c45fad44..dc743812 100644
--- a/src/ai/search.h
+++ b/src/ai/search.h
@@ -190,6 +190,9 @@ public:
     // 撤销着法
     void undoMove();
 
+    void doNullMove();
+    void undoNullMove();
+
 #ifdef TRANSPOSITION_TABLE_ENABLE
     // 清空哈希表
     void clearTT();
diff --git a/src/game/position.cpp b/src/game/position.cpp
index 1b1c345b..8c716d25 100644
--- a/src/game/position.cpp
+++ b/src/game/position.cpp
@@ -1051,6 +1051,18 @@ void StateInfo::changeSideToMove()
     setSideToMove(Player::getOpponent(position->sideToMove));
 }
 
+bool StateInfo::doNullMove()
+{
+    changeSideToMove();
+    return true;
+}
+
+bool StateInfo::undoNullMove()
+{
+    changeSideToMove();
+    return true;
+}
+
 void StateInfo::setTips()
 {
     string winnerStr, t;
diff --git a/src/game/position.h b/src/game/position.h
index 1fbd5ab3..6cccaf54 100644
--- a/src/game/position.h
+++ b/src/game/position.h
@@ -249,6 +249,10 @@ public:
 
     // 着法生成
     int generateMoves(Stack<move_t, MOVE_COUNT> &moves);
+    int generateNullMove(Stack<move_t, MOVE_COUNT> &moves);
+
+    bool doNullMove();
+    bool undoNullMove();
 
     // 判断胜负
     player_t getWinner() const;