ai: search: 解决因 IDS 导致的有时根节点所有子结点都剪枝了的问题

默认不启用, 因为自对弈时长会由44s增长到84s.

include/config.h

@@ -62,6 +62,7 @@
 
 #define IDS_SUPPORT
 
+//#define CLEAR_PRUNED_FLAG_BEFORE_SEARCH
 //define DEEPER_IF_ONLY_ONE_LEGAL_MOVE
 
 #define TRANSPOSITION_TABLE_ENABLE

src/ai/search.cpp

@@ -668,6 +668,12 @@ value_t AIAlgorithm::search(depth_t depth, value_t alpha, value_t beta, Node *no
 
     assert(node->childrenSize != 0);
 
+#ifdef CLEAR_PRUNED_FLAG_BEFORE_SEARCH
+#ifdef SORT_CONSIDER_PRUNED
+    node->pruned = false;
+#endif  // SORT_CONSIDER_PRUNED
+#endif // CLEAR_PRUNED_FLAG_BEFORE_SEARCH
+
     int nchild = node->childrenSize;
     for (int i = 0; i < nchild; i++) {
         doMove(node->children[i]->move);