Mettl Coding Skills 2

Question 1

What is the time complexity of searching for an element in a balanced binary search tree?

Accepted Answer

O(log n)

Answer

A balanced BST halves the search space at each node, giving O(log n) time complexity.

Question 2

Which sorting algorithm has the best average-case time complexity?

Accepted Answer

Merge Sort

Answer

Merge Sort runs in O(n log n) average-case, outperforming the O(n²) algorithms.

Question 3

In Python, what does the following return: `[x**2 for x in range(4)]`?

Accepted Answer

[0, 1, 4, 9]

Answer

range(4) produces 0,1,2,3 and squaring each yields [0, 1, 4, 9].

Question 4

What does the 'virtual' keyword enable in C++?

Accepted Answer

Runtime polymorphism via dynamic dispatch

Answer

The 'virtual' keyword enables runtime polymorphism by using a vtable for dynamic dispatch.

Question 5

Which data structure uses LIFO (Last In, First Out) ordering?

Accepted Answer

Stack

Answer

A Stack follows LIFO: the last element pushed is the first one popped.

Mettl Practice Test