Hackerrank Algorithms 3

Question 1

What is the output of `list(map(lambda x: x**2, [1, 2, 3, 4]))`?

Accepted Answer

[1, 4, 9, 16]

Answer

[2, 4, 6, 8]

Answer

[1, 2, 3, 4]

Answer

[1, 8, 27, 64]

Question 2

Which traversal of a binary tree visits nodes in the order: left subtree, root, right subtree?

Accepted Answer

In-order

Answer

Pre-order

Answer

Post-order

Answer

Level-order

Question 3

What Python built-in can find the greatest common divisor of two integers?

Accepted Answer

math.gcd(a, b)

Answer

math.lcm(a, b)

Answer

int.gcd(a, b)

Answer

fractions.gcd(a, b)

Question 4

A sliding window of size k moves across an array of size n. What is the total number of windows?

Accepted Answer

n - k + 1

Answer

k

Answer

n

Answer

n * k

Question 5

What does `heapq.nlargest(3, [5, 1, 8, 3, 9, 2])` return?

Accepted Answer

[9, 8, 5]

Answer

[1, 2, 3]

Answer

[5, 8, 9]

Answer

[9, 8, 3]

Question 6

Which sorting algorithm has the best average-case and worst-case time complexity of O(n log n)?

Accepted Answer

Merge Sort

Answer

Quicksort

Answer

Bubble Sort

Answer

Insertion Sort

Question 7

In Python, what is the result of `[x for x in range(10) if x % 2 == 0]`?

Accepted Answer

[0, 2, 4, 6, 8]

Answer

[1, 3, 5, 7, 9]

Answer

[0, 1, 2, 3, 4]

Answer

[2, 4, 6, 8, 10]