Binary Tree Node Structure in DSA Go - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a binary tree node?

A binary tree node is a basic unit of a binary tree that contains data and two links: one to the left child and one to the right child.

beginner

Show the Go struct definition for a binary tree node.

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

intermediate

Why do binary tree nodes use pointers for children in Go?

Pointers allow nodes to link to other nodes dynamically and represent absence of a child with nil, saving memory and enabling tree structure.

beginner

What does it mean if a binary tree node's Left or Right pointer is nil?

It means that the node does not have a left or right child respectively, indicating the end of that branch.

beginner

How can you create a new binary tree node with value 5 in Go?

node := &TreeNode{Val: 5, Left: nil, Right: nil}

What fields does a binary tree node typically have?

A Left child pointer, Right child pointer only

B Value, Parent pointer, Next pointer

C Value, Left child pointer, Right child pointer

D Value only

A binary tree node stores a value and pointers to its left and right children.

In Go, what type should the Left and Right fields of a binary tree node be?

A int

B *TreeNode

C TreeNode

D string

Left and Right are pointers to other TreeNode structs, so their type is *TreeNode.

What does a nil pointer in a binary tree node's child field represent?

A No child node exists

B Child node with value zero

C Error in the tree

D Root node

A nil pointer means the node does not have a child in that direction.

How do you declare a binary tree node struct in Go?

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

B struct TreeNode { int Val; TreeNode Left; TreeNode Right }

C class TreeNode { int Val; TreeNode Left; TreeNode Right }

D record TreeNode (int Val, TreeNode Left, TreeNode Right)

Option A shows the correct Go syntax for a binary tree node struct.

Which of these is NOT true about binary tree nodes?

A They can have up to two children

B Child pointers can be nil

C They store a value

D They always have a parent pointer

Binary tree nodes do not always have a parent pointer; it is optional.

Describe the structure of a binary tree node in Go and explain the purpose of each field.

Think about how nodes connect to form a tree.

Explain why pointers are used for child nodes in a binary tree node struct in Go.

Consider how trees grow and shrink.