package main

import "fmt"

type TreeNode struct {
	Val   int
	Left  *TreeNode
	Right *TreeNode
}

func inorder(root *TreeNode) {
	if root == nil {
		return
	}
	inorder(root.Left)
	fmt.Print(root.Val)
	inorder(root.Right)
}

func preorder(root *TreeNode) {
	if root == nil {
		return
	}
	fmt.Print(root.Val)
	preorder(root.Left)
	preorder(root.Right)
}

func postorder(root *TreeNode) {
	if root == nil {
		return
	}
	postorder(root.Left)
	postorder(root.Right)
	fmt.Print(root.Val)
}

func reverserOrder(root *TreeNode) {
  if root == nil {
    return
  }
  reverserOrder(root.Right)
  fmt.Print(root.Val)
  reverserOrder(root.Left)
}

func traverse(root *TreeNode, res *[]int){
    if root == nil {
        return
    }
    traverse(root.Left, res)
    *res = append(*res, root.Val)
    traverse(root.Right, res)
}
func inorderTraversal(root *TreeNode) []int {
    var result []int
    traverse(root, &result)
    return result
}

func main() {
	n10 := TreeNode{Val: 2}
	n9 := TreeNode{Val: 5}
	n8 := TreeNode{Val: 7}
	n7 := TreeNode{Val: 6, Left: &n9, Right: &n8}
	n6 := TreeNode{Val: 3, Left: &n10}
	n5 := TreeNode{Val: 4, Left: &n6, Right: &n7}

	// inorder(&n5)
	// fmt.Println()
	// preorder(&n5)
	// fmt.Println()
	// postorder(&n5)
	// fmt.Println()
	// reverserOrder(&n5)
  res := inorderTraversal(&n5)
  fmt.Print(res)
}