fix(avl tree): fix all issue

codes/cpp/chapter_tree/avl_tree.cpp

@@ -34,14 +34,14 @@ bool AvlTree::isBalance(const TreeNode *p) {
 // 获取当前结点的平衡因子
 int AvlTree::getBalanceFactor(const TreeNode *p) {
     if (p->left == nullptr && p->right == nullptr) { return 0; }
-    else if (p->left == nullptr) { return (-p->right->height); }
-    else if (p->right == nullptr) { return p->left->height; }
+    else if (p->left == nullptr) { return (-1 - p->right->height); }
+    else if (p->right == nullptr) { return p->left->height + 1; }
     else { return p->left->height - p->right->height; }
 }
 
 // 更新结点高度
 void AvlTree::updateHeight(TreeNode *p) {
-    if (p->left == nullptr && p->right == nullptr) { p->height = 1; }
+    if (p->left == nullptr && p->right == nullptr) { p->height = 0; }
     else if (p->left == nullptr) { p->height = p->right->height + 1; }
     else if (p->right == nullptr) { p->height = p->left->height + 1; }
     else { p->height = std::max(p->left->height, p->right->height) + 1; }

codes/cpp/include/TreeNode.hpp

@@ -12,7 +12,7 @@
  */
 struct TreeNode {
     int val{};
-    int height = 1;
+    int height = 0;
     TreeNode *parent{};
     TreeNode *left{};
     TreeNode *right{};