Uncommon Words from Two Sentences — LeetCode 884 Python Solution

The problem

A sentence is a string of single-space separated words where each word consists only of lowercase letters. A word is uncommon if it appears exactly once in one of the sentences, and does not appear in the other sentence.

Python solution

class Solution:
    def uncommonFromSentences(self, s1: str, s2: str) -> List[str]:
        cnt = Counter(s1.split()) + Counter(s2.split())
        return [s for s, v in cnt.items() if v == 1]

Complexity

Pattern: Hash Map

Trade memory for time: remember what you have seen so the second pass never happens. LeetCode 884. Uncommon Words from Two Sentences is filed here on both counts: the reference solution below belongs to the algorithm family this hub collects, and LeetCode tags it Hash Table and Counting.

The hash map guide has the Python template for the pattern and the 709 LeetCode problems that use it.

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