Hackerrank Algorithms 2

Question 1

What is the time complexity of binary search on a sorted list of n elements?

Accepted Answer

O(log n)

Answer

O(n)

Answer

O(n log n)

Answer

O(1)

Question 2

Which Python built-in function returns the index of the leftmost value in a sorted list that is greater than or equal to a target, using the `bisect` module?

Accepted Answer

bisect.bisect_left

Answer

bisect.bisect_right

Answer

bisect.insort

Answer

bisect.find

Question 3

Given a list `nums = [3, 1, 4, 1, 5, 9]`, what does `sorted(nums, reverse=True)` return?

Accepted Answer

[9, 5, 4, 3, 1, 1]

Answer

[1, 1, 3, 4, 5, 9]

Answer

[3, 1, 4, 1, 5, 9]

Answer

[9, 5, 4, 1, 3, 1]

Question 4

Which algorithm sorts by repeatedly finding the minimum element from the unsorted portion and placing it at the beginning?

Accepted Answer

Selection Sort

Answer

Bubble Sort

Answer

Insertion Sort

Answer

Merge Sort

Question 5

What is the worst-case time complexity of quicksort?

Accepted Answer

O(n^2)

Answer

O(n log n)

Answer

O(n)

Answer

O(log n)

Question 6

In Python, what does `collections.Counter([1,1,2,3,3,3])` return?

Accepted Answer

Counter({3: 3, 1: 2, 2: 1})

Answer

[1, 1, 2, 3, 3, 3]

Answer

Counter({1: 2, 3: 3, 2: 1})

Answer

{1: 2, 2: 1, 3: 3}

Question 7

Which data structure gives O(1) average time for insert, delete, and lookup?

Accepted Answer

Hash table (dict/set)

Answer

List

Answer

Sorted list

Answer

Binary search tree