feat(go/tree): support array binary tree (#655)

codes/go/chapter_tree/array_binary_tree_test.go

@@ -0,0 +1,47 @@
+// File: array_binary_tree_test.go
+// Created Time: 2023-07-24
+// Author: Reanon (793584285@qq.com)
+
+package chapter_tree
+
+import (
+	"fmt"
+	"testing"
+
+	. "github.com/krahets/hello-algo/pkg"
+)
+
+func TestArrayBinaryTree(t *testing.T) {
+	// 初始化二叉树
+	// 这里借助了一个从数组直接生成二叉树的函数
+	arr := []any{1, 2, 3, 4, nil, 6, 7, 8, 9, nil, nil, 12, nil, nil, 15}
+	root := SliceToTree(arr)
+	fmt.Println("\n初始化二叉树")
+	fmt.Println("二叉树的数组表示：")
+	fmt.Println(arr)
+	fmt.Println("二叉树的链表表示：")
+	PrintTree(root)
+
+	// 数组表示下的二叉树类
+	abt := newArrayBinaryTree(arr)
+
+	// 访问节点
+	i := 1
+	l := abt.left(i)
+	r := abt.right(i)
+	p := abt.parent(i)
+	fmt.Println("\n当前节点的索引为", i, "，值为", abt.val(i))
+	fmt.Println("其左子节点的索引为", l, "，值为", abt.val(l))
+	fmt.Println("其右子节点的索引为", r, "，值为", abt.val(r))
+	fmt.Println("其父节点的索引为", p, "，值为", abt.val(p))
+
+	// 遍历树
+	res := abt.levelOrder()
+	fmt.Println("\n层序遍历为：", res)
+	res = abt.preOrder()
+	fmt.Println("前序遍历为：", res)
+	res = abt.inOrder()
+	fmt.Println("中序遍历为：", res)
+	res = abt.postOrder()
+	fmt.Println("后序遍历为：", res)
+}