Question Discussion & Solution

Answer: Option 3

Concept:

Tree:

• A tree consists of nodes or vertices that store information and often are labeled by a number or a letter.
• A tree consists of directed edges or undirected edges or both.
• The number of subtrees of a node is called its degree.
• A leaf or a terminal node is a node of degree zero
• A node that is not a leaf is called an interior node or an internal node
• The degree of a node is the number of its children. The degree of a tree is the maximum degree of any of its nodes.

Ancestors of a node in a Tree: 

The ancestor nodes of a node are all parent nodes of that particular node.

Explanation: 

Consider the following Binary Tree 

Every node except the root node (A) has ancestors.

Hence in a tree, the only node that has no ancestors is the root node. (only one node possible)

Additional Information

Full Binary Tree: 

A full binary tree is a binary tree in which each node has exactly two or 0 children.

Complete Binary Tree:

A complete binary tree is a binary tree in which

1. except last level tree is completely filled.
2. The last level is filled from left to right.

Perfect Binary Tree: 

A perfect binary tree is a binary tree in which

1. all interior node or internal nodes has 2 children.
2. all leaves are at the same level.

Balanced Binary Tree: 

A Balanced Binary tree is a binary tree in which at any node height of the left subtree and right subtree do not differ by more than 1.

Important Points

1. A tree with n nodes has n - 1 edge.

2.  consider a nonempty binary tree with n0 leaves and n2 nodes of degree two (internal nodes). Then
n0 = n2 + 1
Applications of Trees: 
1. Huffman Coding
2. Evaluation of Arithmetic Expressions using Expression trees

49 ÷ 7 = 7,

70 ÷ 7 = 10,

91 ÷ 7 = 13,

99 ÷ 7 = 14.14

So, 49, 70 and 91 are the multiples of 7 while 99 is not a multiple of 7.

Explanation:

• The purpose of regression testing is to confirm that a recent program or code change has not adversely affected existing features.
• Regression testing is nothing but a full or partial selection of already executed test cases that are re-executed to ensure existing functionalities work fine.
• This testing is done to make sure that new code changes should not have side effects on the existing functionalities. It ensures that the old code still works once the new code changes are done.

The purpose of regression testing is to select test cases partially or fully to ensure existing functionalities work fine. Thus, regression testing is primarily related to functional testing

Need of Regression Testing

• Regression Testing is required when there is a change in requirements and code is modified according to the requirement or when one of the following has been done.
  • New feature is added to the software
  • Defect fixing
  • Performance issue fix

According to given information,

Whatever be the distance covered by the person, when the man stops he is facing south.

Hence, the answer is ‘South’.