Python Coding
Challenges

Dicts & Sets easy

Word frequency

Return a dict mapping each word to its count in the sentence.

dict counter

+10 pts 10m

Dicts & Sets easy

List intersection

Return the sorted list of elements common to both lists.

sets intersection

+8 pts 8m

Dicts & Sets medium

Group anagrams

Group words that are anagrams of each other.

dict sorting strings

+22 pts 20m

Dicts & Sets easy

First non-repeating character

Find the index of the first character that appears only once.

dict strings counter

+12 pts 12m

Dicts & Sets easy

Most frequent element

Return the element that appears most often in a list.

counter dict

+8 pts 8m

Dicts & Sets medium

Subarray sum equals K

Count the number of contiguous subarrays whose sum equals k.

prefix-sum dict arrays

+28 pts 25m