第二题初步完成

homework4/BiTree.cpp

@@ -60,6 +60,29 @@ void BiTree::insertNode(BiTree*& bt, int value)
     }
 }
 
+BiTree* BiTree::build_from_preorder_string(const std::string& preorder, size_t& index)
+{
+    if (index >= preorder.size() || preorder[index] == '#')
+    {
+        index++;
+        return nullptr;
+    }
+
+    BiTree* node = createNode(preorder[index++] - 'A' + 1);
+    node->left = build_from_preorder_string(preorder, index);
+    node->right = build_from_preorder_string(preorder, index);
+
+    return node;
+}
+
+void BiTree::inOrder(std::ostringstream& oss) const
+{
+    if (this == nullptr) return;
+    if (left)left->inOrder(oss);
+    oss << static_cast<char>(data + 'A' - 1);
+    if (right)right->inOrder(oss);
+}
+
 
 void toStringHelper(const BiTree* node, std::ostringstream& oss, const std::string& prefix, bool isLeft,
                     bool hasSibling)
@@ -85,3 +108,15 @@ std::string BiTree::toString()
     return oss.str();
 }
 
+void BiTree::destory()
+{
+    if (left)
+    {
+        left->destory();
+    }
+    if (right)
+    {
+        right->destory();
+    }
+}
+