Check if Two Trees are Symmetric in DSA Go - Build from Scratch

Check if Two Trees are Symmetric

📖 Scenario: You are working with two simple binary trees representing family trees. You want to check if these two trees are mirror images of each other, meaning they are symmetric.

🎯 Goal: Build a Go program that creates two binary trees, sets a helper variable, writes a function to check if the trees are symmetric, and prints the result.

📋 What You'll Learn

Create two binary trees using the TreeNode struct with exact values

Create a helper variable result of type bool

Write a function isSymmetric that checks if two trees are symmetric

Print the value of result

💡 Why This Matters

🌍 Real World

Checking if two trees are symmetric is useful in comparing hierarchical data structures like family trees, organizational charts, or XML/JSON data.

💼 Career

Understanding tree symmetry helps in software development roles involving data structure manipulation, algorithm design, and problem-solving.

1

Create two binary trees

Create two binary trees using the TreeNode struct with these exact values: root1 with value 1, left child 2, right child 3; and root2 with value 1, left child 3, right child 2.

DSA Go

package main

import "fmt"

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

func main() {
    // Create root1 tree
    // Your code here
}

Hint

Use the &TreeNode{Val: value} syntax to create nodes and assign left and right children.

2

Create a helper variable

Create a boolean variable called result and set it to false inside the main function.

DSA Go

package main

import "fmt"

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

func main() {
    root1 := &TreeNode{Val: 1}
    root1.Left = &TreeNode{Val: 2}
    root1.Right = &TreeNode{Val: 3}

    root2 := &TreeNode{Val: 1}
    root2.Left = &TreeNode{Val: 3}
    root2.Right = &TreeNode{Val: 2}

    // Create a boolean variable result and set it to false
    // Your code here
}

Hint

Use result := false to create and initialize the boolean variable.

3

Write the function to check symmetry

Write a function called isSymmetric that takes two pointers to TreeNode named t1 and t2 and returns a bool. It should return true if both trees are symmetric (mirror images), otherwise false. Use recursion to compare nodes. Then, inside main, set result to the call isSymmetric(root1, root2).

DSA Go

func isSymmetric(t1 *TreeNode, t2 *TreeNode) bool {
    if t1 == nil && t2 == nil {
        return true
    }
    if t1 == nil || t2 == nil {
        return false
    }
    if t1.Val != t2.Val {
        return false
    }
    return isSymmetric(t1.Left, t2.Right) && isSymmetric(t1.Right, t2.Left)
    result = isSymmetric(root1, root2)

Hint

Check if both nodes are nil, then if one is nil, then if values differ. Recursively check left of one with right of other and vice versa.

4

Print the result

Print the value of the boolean variable result inside the main function.

DSA Go

Hint

Use fmt.Println(result) to print the boolean value.