Preorder traversal of a Binary Tree in Go (Golang)

Overview

In the preorder traversal of a binary tree, we follow the below order

• Visit Root

• Vist Left Subtree

• Visit Right Subtree

For example, let’s say we have below binary tree

Then preorder traversal would be

[1 2 4 3 5 6]

Program

Here is the program for the same

package main

import (
	"fmt"
)

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

func preorderTraversal(root *TreeNode) []int {
	if root == nil {
		return nil
	}

	left := preorderTraversal(root.Left)
	right := preorderTraversal(root.Right)

	output := make([]int, 0)

	output = append(output, root.Val)
	output = append(output, left...)
	output = append(output, right...)
	return output
}

func main() {
	root := TreeNode{Val: 1}
	root.Left = &TreeNode{Val: 2}
	root.Left.Left = &TreeNode{Val: 4}
	root.Right = &TreeNode{Val: 3}
	root.Right.Left = &TreeNode{Val: 5}
	root.Right.Right = &TreeNode{Val: 6}

	output := preorderTraversal(&root)
	fmt.Println(output)

}

Output

[1 2 4 3 5 6]

Note: Check out our Golang Advanced Tutorial. The tutorials in this series are elaborative and we have tried to cover all concepts with examples. This tutorial is for those who are looking to gain expertise and a solid understanding of golang – Golang Advance Tutorial

Also if you are interested in understanding how all design patterns can be implemented in Golang. If yes, then this post is for you –All Design Patterns Golang