Add implementation of array binary tree.

Rewrite the tree serialization and deserialization methods.
Add applications of array and linked list.

codes/cpp/chapter_backtracking/preorder_traversal_iii_compact.cpp

@@ -29,7 +29,7 @@ static void preOrder(TreeNode *root) {
 
 /* Driver Code */
 int main() {
-    TreeNode *root = vecToTree(vector<int>{1, 7, 3, 4, 5, 6, 7});
+    TreeNode *root = vectorToTree(vector<int>{1, 7, 3, 4, 5, 6, 7});
     cout << "\n初始化二叉树" << endl;
     printTree(root);