Hackerrank Python Data Structures & Algorithms

Question 1

What is the time complexity of searching for an element in a Python dictionary?

Accepted Answer

O(1) average case

Answer

O(n)

Answer

O(log n)

Answer

O(n²)

Question 2

What is the output of the following Python code?

my_list = [1, 2, 3, 4, 5]
print(my_list[1:4])

Accepted Answer

[2, 3, 4]

Answer

[1, 2, 3, 4]

Answer

[2, 3, 4, 5]

Answer

[1, 2, 3]

Question 3

Which Python data structure would be most efficient for implementing a FIFO (First-In-First-Out) queue?

Accepted Answer

collections.deque

Answer

list

Answer

set

Answer

tuple

Question 4

What does the Python `sorted()` function return when called on a dictionary?

Accepted Answer

A sorted list of the dictionary's keys

Answer

A sorted dictionary

Answer

A sorted list of the dictionary's values

Answer

A sorted list of key-value tuples

Question 5

What is a list comprehension in Python?

Accepted Answer

A concise syntax for creating lists by applying an expression to each item in an iterable

Answer

A method for sorting lists in place

Answer

A way to convert lists to dictionaries

Answer

A function that counts elements in a list

Question 6

What is the difference between a Python tuple and a list?

Accepted Answer

Tuples are immutable and lists are mutable

Answer

Tuples can only store integers

Answer

Lists are faster than tuples for all operations

Answer

Tuples use curly braces and lists use square brackets