Data Structures and Algorithm

What is a data structure?

• A programming language

• A collection of algorithms

• A way to store and organize data

• A type of computer hardware

Answer explanation

A data structure is specifically defined as a way to store and organize data efficiently, making it easier to access and manipulate. The other options do not accurately describe what a data structure is.

Which data structure is used for implementing recursion?

• Fibonacci

• Function Calls

• Stack

• Queue

Answer explanation

Recursion relies on the stack data structure to keep track of function calls. Each recursive call is pushed onto the stack, and when a base case is reached, the calls are popped off, allowing the program to return to previous states.

The data structure required for Breadth First Traversal on a graph is?

• Array

• Stack

• Tree

• Queue

Answer explanation

Breadth First Traversal uses a Queue to explore nodes level by level. Nodes are enqueued as they are discovered and dequeued for processing, ensuring that all nodes at the current level are processed before moving to the next.

What is an AVL tree?

• a tree which is unbalanced and is a height balanced tree

• a tree which is balanced and is a height balanced tree

• a tree with atmost 3 children

• a tree with three children

Answer explanation

An AVL tree is a type of binary search tree that maintains balance by ensuring the heights of the two child subtrees of any node differ by no more than one. This makes it a height-balanced tree, confirming the correct choice.

what is a dequeue?

• a queue implemented with both singly and doubly linked lists

• a queue with insert/delete defined for front side of the queue

• a queue with insert/delete defined for both front and rear end of the queue

• a queue implemented with a doubly linked list

Answer explanation

A dequeue, or double-ended queue, allows insertion and deletion of elements from both the front and rear ends, making it more versatile than a standard queue, which only allows these operations at one end.

What is the time complexity of Bubble Sort in the average case?

• o(n²)

• o(n log n)

• o(n³)

• o(n)

Answer explanation

The average case time complexity of Bubble Sort is O(n²) because it involves nested loops, where each element is compared with every other element, leading to quadratic growth in the number of comparisons as the input size increases.

algorithm to find the shortest path from a source node to all other nodes in a graph with non-negative weights?

• Breadth-First Search (BFS)

• Depth-First Search (DFS)

• Bellman-Ford Algorithm

• Dijkstra's Algorithm

Answer explanation

Dijkstra's Algorithm is specifically designed to find the shortest path in graphs with non-negative weights, making it the correct choice. BFS and DFS do not account for weights, while Bellman-Ford handles negative weights.

what data structure is used for implementing an efficient priority queue with multiple priority levels?

• Queue

• Heap

• Stack

• Array

Answer explanation

A heap is the most efficient data structure for implementing a priority queue with multiple priority levels, as it allows for quick access to the highest (or lowest) priority element, making insertion and deletion operations efficient.

what is the time complexity of inserting an element at the beginning of a linked list?

• o(1)

• o(n)

• o(log n)

• o(n log n)

Answer explanation

Inserting an element at the beginning of a linked list involves adjusting the head pointer to the new node, which takes constant time. Therefore, the time complexity is O(1), making it the correct choice.

what is a circular linked list?

• a list where each node points to the next 

• a list where the last node points to the first node.

• a list where each node points to itself

• a list where the nodes are in a circle

Answer explanation

A circular linked list is defined by its last node pointing back to the first node, creating a loop. This allows for continuous traversal of the list without reaching a null reference, unlike a standard linked list.