Python Libraries for DSA Interviews

Question 1

What are all of the functions and import statements for heaps?

Answer 1

import heapq

heapq. heappop(heap_list)
heapq. heappush(heap_list, val)
heapq. heapify(list)

heapq. nlargest(k, iterable, key)
heapq. nsmallest(k, iterable, key)

heapq. heappushpop(heap, elem)
heapq. heapreplace(heap, elem)

Question 2

What are the Python functions to create a heap and it’s basic functionality?

Answer 2

• heapq. heappop(heap_list)
• heapq. heappush(heap_list, val)
• heapq. heapify(list)

Question 3

What are the Python functions to find the k largest or k smallest of a heap?

Answer 3

• heapq. nlargest(k, iterable, key)
• heapq. nsmallest(k, iterable, key)

Question 4

What are some useful methods in the “collections” library?

Answer 4

• defaultdict
• Counter
• deque

Question 5

What is the import statement for generating permutations and combinations?

Answer 5

• from itertools import permutations
• from itertools import combinations

Question 6

What import statement do you use when you want a data structure with the following properties?
* unique values
* ordering

Answer 6

from collections import OrderedDict