Diameter of Binary Tree in DSA Go - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define the TreeNode struct with integer value and pointers to left and right children.

DSA Go

type TreeNode struct {
    Val   int
    Left  *[1]
    Right *TreeNode
}

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ABinaryNode

BTree

CTreeNode

DNode

Attempts:

3 left

💡 Hint

Common Mistakes

Using a different struct name for the child pointers.

Forgetting the pointer symbol '*' before the struct name.

The left child pointer must be of type *TreeNode to correctly reference the same struct type.

2fill in blank

medium

Complete the code to calculate the maximum of two integers a and b.

DSA Go

func max(a, b int) int {
    if a [1] b {
        return a
    }
    return b
}

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A<

B>

C==

D<=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<' instead of '>' causing minimum to be returned.

Using '==' which only checks equality.

To return the maximum, check if a is greater than b.

3fill in blank

hard

Fix the error in the recursive function to compute the height of a binary tree node.

DSA Go

func height(root *TreeNode) int {
    if root == nil {
        return 0
    }
    leftHeight := height(root.[1])
    rightHeight := height(root.Right)
    if leftHeight > rightHeight {
        return leftHeight + 1
    }
    return rightHeight + 1
}

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ARight

Bleft

Cright

DLeft

Attempts:

3 left

💡 Hint

Common Mistakes

Using lowercase 'left' which causes compilation error.

Confusing 'Right' and 'left' fields.

The field name is 'Left' with uppercase L as per Go struct field naming conventions.

4fill in blank

hard

Fill both blanks to update the diameter and return the height of the current node.

DSA Go

func diameterHelper(root *TreeNode, diameter *int) int {
    if root == nil {
        return 0
    }
    leftHeight := diameterHelper(root.Left, diameter)
    rightHeight := diameterHelper(root.Right, diameter)
    *diameter = max(*diameter, leftHeight [1] rightHeight)
    return max(leftHeight, rightHeight) [2] 1
}

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A+

B*

C-

D/

Attempts:

3 left

💡 Hint

Common Mistakes

Using multiplication or subtraction instead of addition.

Returning sum instead of max for height.

The diameter is updated by sum of left and right heights; height is max of left/right plus 1.

5fill in blank

hard

Fill all three blanks to implement the diameter of binary tree function using helper.

DSA Go

func diameterOfBinaryTree(root *TreeNode) int {
    diameter := 0
    var [1] func(*TreeNode) int
    [1] = func(node *TreeNode) int {
        if node == nil {
            return 0
        }
        left := [2](node.Left)
        right := [2](node.Right)
        if left + right > diameter {
            diameter = left + right
        }
        if left > right {
            return left + 1
        }
        return right + 1
    }
    [1](root)
    return diameter
}

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Aheight

BdiameterHelper

CheightHelper

DcalcHeight

Attempts:

3 left

💡 Hint

Common Mistakes

Using different names for function definition and calls causing errors.

Not updating diameter correctly inside helper.

The anonymous function is named 'height' and recursively called to compute heights and update diameter.