Tree Terminology Root Leaf Height Depth Level in DSA Go - Practice Problems & Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Identify the root node in a tree

In a tree data structure, which node is called the root?

A The node with the highest depth

B The node with no children

C The node with the lowest height

D The node with no parent

💡 Hint

Think about where the tree starts growing from.

The root node is the topmost node in a tree and has no parent node.

❓ Predict Output

intermediate

Output the leaf nodes of a tree

Given the following tree structure, which nodes are leaves?

DSA Go

type Node struct {
    Value int
    Children []*Node
}

// Tree:
//       1
//     /   \
//    2     3
//   / \     \
//  4   5     6

// Leaves are nodes with no children.

A [4, 5, 6]

B [1, 2, 3]

C [2, 3, 6]

D [1, 4, 5]

💡 Hint

Leaves have no children nodes.

Nodes 4, 5, and 6 have no children, so they are leaves.

❓ Predict Output

advanced

Calculate the height of a node in a tree

What is the height of node 2 in the following tree? // Tree: // 1 // / \ // 2 3 // / \ \ // 4 5 6 // Height is the number of edges on the longest path from the node to a leaf.

A 0

B 3

C 1

D 2

💡 Hint

Count edges from node 2 down to its farthest leaf.

Node 2 has children 4 and 5 which are leaves. The longest path from 2 to a leaf has 1 edge (to 4 or 5), so height is 1.

🧠 Conceptual

advanced

Understanding depth and level of a node

Which statement correctly describes the depth and level of a node in a tree?

A Depth is the number of leaves under the node; level is the number of ancestors

B Depth is the number of edges from the root to the node; level is depth plus one

C Depth and level are always equal to the height of the node

D Depth is the number of children of the node; level is the number of siblings

💡 Hint

Think about how far a node is from the root.

Depth counts edges from root to node; level counts nodes from root (starting at 1). So level = depth + 1.

🔧 Debug

expert

Find the error in height calculation code

What error will this Go code produce when calculating the height of a tree node? func height(node *Node) int { if node == nil { return -1 } maxHeight := -1 for _, child := range node.Children { h := height(child) if h > maxHeight { maxHeight = h } } return maxHeight + 1 } // Node struct has Children slice.

A Returns incorrect height for leaf nodes

B Causes infinite recursion

C Returns -1 for empty tree correctly

D Panics due to nil pointer dereference

💡 Hint

Check base case and initial maxHeight value.

For leaf nodes (no children), maxHeight is initialized to -1 and remains -1, so the function returns 0. This correctly represents the height of a leaf node. The original code initialized maxHeight to 0, causing the function to return 1 for leaf nodes, which is incorrect.