Data Structures & Algorithms

What is the time complexity of inserting an element at the end of an array (without resizing)?

• O(1)

• O(n)

• O(log n)

• O(n log n)

Which data structure is most suitable for performing undo operations?

• Queue

• Stack

• Hash table

• Array

What is a main advantage of using a hash table compared to an array for searching elements?

• Constant time access using a key

• Elements are sorted

• Uses less memory

• No collisions

Among the following traversal orders, which order is correct for in-order traversal of a binary search tree?

• Root -> Left -> Right

• Left -> Root -> Right

• Right -> Root -> Left

• Root -> Right -> Left

What is the main difference between a stack and a queue?

• Stack uses FIFO, Queue uses LIFO

• Stack uses LIFO, Queue uses FIFO

• Stack only stores numbers, Queue stores strings

• Stack is dynamic, Queue is static

In a min-heap, which of the following is always true?

• The root has the largest value

• All leaves have the same value

• The root has the smallest value

• All nodes are sorted in ascending order

Which sorting algorithm has the best average time complexity among the following algorithms?

• Selection sort

• Bubble sort

• Quick sort

• Insertion sort

Which data structure is best for implementing a priority queue?

• Stack

• Array

• Linked list

• Heap

In a hash table, what happens when two keys map to the same index?

• One of them is deleted

• A collision occurs

• They are sorted

• The hash function is replaced

What is the base case in recursion?

• A condition that calls the function again

• The smallest input that stops the recursion

• A loop that runs to the end

• A function without a return value