Computer Knowledge

Data Structures and Algorithms

1,256 Questions

Data Structures and Algorithms form the core of computer science, focusing on arrays, linked lists, trees, and sorting mechanisms. These concepts are essential for solving complex computational problems efficiently. Test takers preparing for technical and administrative IT exams will find these questions highly relevant.

Array OperationsLinked List ApplicationsSorting AlgorithmsTree Data StructuresMultilevel IndexingAlgorithm Time Complexity

Data Structures and Algorithms Questions

Multiple choice

Find the odd one out.

  1. Ascending priority queue - Min Heap

  2. Descending priority queue - Max Heap

  3. Binary Search Tree - Sorting

  4. B-Tree - Index Sequential Search
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The other options pair a data structure with its primary application or property (Priority Queues with Heaps, B-Trees with indexing). A Binary Search Tree is a data structure, not a sorting algorithm itself, though it can be used for sorting.

Multiple choice

How many constructors are there for LinkedHashSet?

  1. 6

  2. 5

  3. 4

  4. 3

  5. 2
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

This is the correct answer because there are four constructors in the LinkedHashSet. These are :-LinkedHashSet () LinkedHashSet (c : Collection) LinkedHashSet (initialcapacity : int) LinkedHashSet (initialcapacity : int , loadfactor : float). So, this is the correct answer.

Multiple choice

Consider the following program fragment for reversing the digits in a given integer to obtain a new integer. Let n = d1d2... dm. int n, rev; rev = 0; while (n > 0) { rev = rev * 10 + n % 10; n = n/10; } The loop invariant condition at the end of the ith iteration is

  1. n = d1d2... dm-i....and rev = dmdm-1..dm-i+1

  2. n = dm-i+1...dm-1dm (or) rev = dm-i...d2d1

  3. n ¹ rev

  4. n = d1d2...dm (or) rev = dm...d2d1
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The loop reverses the integer. After i iterations, the last i digits of n have been moved to the front of rev in reverse order. Thus, n contains the remaining digits and rev contains the reversed prefix.

Multiple choice

The following numbers are inserted into an empty binary search tree in the given order: 10, 1, 3, 5, 15, 12, 16. What is the height of the binary search tree (the height is the maximum distance of a leaf node from the root)?

  1. 2

  2. 3

  3. 4

  4. 6
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Inserting 10, 1, 3, 5, 15, 12, 16 into a BST creates a tree where 10 is the root, 1 is the left child, 3 is the right child of 1, 5 is the right child of 3, 15 is the right child of 10, 12 is the left child of 15, and 16 is the right child of 15. The longest path from the root (10) to a leaf (5 or 16) has 3 edges (10-1-3-5).

Multiple choice

Postorder traversal of a binary search tree T produces the following sequence of keys:

10, 9, 23, 22, 27, 25, 15, 50, 95, 60, 40, 29

Which of the following sequences of keys can be the result of an inorder traversal of the tree T?

  1. 9, 10, 15, 22, 23, 25, 27, 29, 40, 50, 60, 95

  2. 9, 10, 15, 22, 40, 50, 60, 95, 23, 25, 27, 29

  3. 29, 15, 9, 10, 25, 22, 23, 27, 40, 60, 50, 95

  4. 95, 50, 60, 40, 27, 23, 22, 25, 10, 9, 15, 29

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Option (1) is correct.

Multiple choice

Consider the following C program segment struct CellNode { struct CellNode *leftChild ; int element; struct CellNode *rightChild ; }; int DoSomething (struct CellNode *ptr) { int value = 0 ; if (ptr ! = NULL) { if (ptr->leftChild ! = NULL) value = 1 + DoSomething (ptr - > leftChild); if (ptr - > rightChild ! = NULL) value = max (value, 1 + DoSomething (ptr - > rightChild)) ; } return (value); } The value returned by the function do something when a pointer to the root of a non-empty tree is passed as argument is

  1. the number of leaf nodes in the tree

  2. the number of nodes in the tree

  3. the number of internal nodes in the tree

  4. the height of the tree
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The function recursively calculates the maximum depth of the tree. For each node, it returns 1 plus the maximum of the heights of its left and right subtrees, which is the definition of tree height.

Multiple choice

How can we increase the efficiency of the doubly linked list ?

  1. By accessing the last element of the list.

  2. By accessing any element from the list.

  3. By traversing the list in left or right direction from node.

  4. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

When a linked list is connected doubly, i.e doubly linked list in which each node contains the address of next as well as previous node is very efficient other than we transverse the list from any direction of side of any node. 

Multiple choice

Consider a hashing function that resolves collision by quadratic probing. Assume the address space to be indexed from 1 to 8. If a collision occurs at position 4, which of the following locations will never be probed?

  1. 4

  2. 5

  3. 8

  4. 2
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Quadratic probing uses the sequence (h(k) + i^2) mod m. Starting at 4 with m=8, the sequence is 4, (4+1) mod 8 = 5, (4+4) mod 8 = 0 (or 8 if 1-indexed), (4+9) mod 8 = 5, (4+16) mod 8 = 4. Since the probe sequence repeats, locations like 2, 3, 6, and 7 are never reached.