#####   ######  #####    ###    #   #  ###  #   #  ######
##  ##  ##      ##  ##  ## ##   #   #   #   #   #  ##
#####   ####    #####   #   #   #   #   #   #   #  ####
##  #   ##      ##      ## ##    # #    #    # #   ##
##   #  ######  ##       ###      #    ###    #    ######

$ curl repovive.com/roadmaps/python/tuples-sets/count-unique-implementation

░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░███████████████████████████████████████████████████████████████████████████

#####   ######  #####    ###    #   #  ###  #   #  ######
##  ##  ##      ##  ##  ## ##   #   #   #   #   #  ##
#####   ####    #####   #   #   #   #   #   #   #  ####
##  #   ##      ##      ## ##    # #    #    # #   ##
##   #  ######  ##       ###      #    ###    #    ######

$ curl repovive.com/roadmaps/python/tuples-sets/count-unique-implementation

Repovive

Count Unique - Implementation - Tuples & Sets | Python | Repovive

Repovive.

Python9 sections · 462 units23h total

Open in Course

Count Unique - Implementation

The code

Here's the solution:

def count_unique_words(sentence):
    words = sentence.split()
    unique_words = set(words)
    return len(unique_words)

Or more concisely:

def count_unique_words(sentence):
    return len(set(sentence.split()))

Time: $O(n)$ where $n$ is the number of words. Space: $O(u)$ where $u$ is the number of unique words.

The set handles all the deduplication work. Your job is just to know it exists.