feat(tree/avl_tree): add go code

codes/go/chapter_tree/avl_tree_test.go

@@ -0,0 +1,54 @@
+// File: avl_tree_test.go
+// Created Time: 2023-01-08
+// Author: Reanon (793584285@qq.com)
+
+package chapter_tree
+
+import (
+	"fmt"
+	"testing"
+
+	. "github.com/krahets/hello-algo/pkg"
+)
+
+func TestAVLTree(t *testing.T) {
+	/* 初始化空 AVL 树 */
+	tree := newAVLTree()
+	/* 插入结点 */
+	// 请关注插入结点后，AVL 树是如何保持平衡的
+	testInsert(tree, 1)
+	testInsert(tree, 2)
+	testInsert(tree, 3)
+	testInsert(tree, 4)
+	testInsert(tree, 5)
+	testInsert(tree, 8)
+	testInsert(tree, 7)
+	testInsert(tree, 9)
+	testInsert(tree, 10)
+	testInsert(tree, 6)
+
+	/* 插入重复结点 */
+	testInsert(tree, 7)
+
+	/* 删除结点 */
+	// 请关注删除结点后，AVL 树是如何保持平衡的
+	testRemove(tree, 8) // 删除度为 0 的结点
+	testRemove(tree, 5) // 删除度为 1 的结点
+	testRemove(tree, 4) // 删除度为 2 的结点
+
+	/* 查询结点 */
+	node := tree.search(7)
+	fmt.Printf("\n查找到的结点对象为 %#v ，结点值 = %d \n", node, node.Val)
+}
+
+func testInsert(tree *avlTree, val int) {
+	tree.insert(val)
+	fmt.Printf("\n插入结点 %d 后，AVL 树为 \n", val)
+	PrintTree(tree.root)
+}
+
+func testRemove(tree *avlTree, val int) {
+	tree.remove(val)
+	fmt.Printf("\n删除结点  %d 后，AVL 树为 \n", val)
+	PrintTree(tree.root)
+}