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Word Subsets

Problem Statement​

You are given two string arrays words1 and words2.

A string b is a subset of string a if every letter in b occurs in a including multiplicity.

  • For example, "wrr" is a subset of "warrior" but is not a subset of "world".

A string a from words1 is universal if for every string b in words2, b is a subset of a.

Return an array of all the universal strings in words1. You may return the answer in any order.

Leetcode Link

Example 1:​

Input: words1 = ["amazon","apple","facebook","google","leetcode"], words2 = ["e","o"]
Output: ["facebook","google","leetcode"]

Example 2:​

Input: words1 = ["amazon","apple","facebook","google","leetcode"], words2 = ["l","e"]
Output: ["apple","google","leetcode"]

Constraints:​

  • 1 <= words1.length, words2.length <= 104
  • 1 <= words1[i].length, words2[i].length <= 10
  • words1[i] and words2[i] consist only of lowercase English letters.
  • All the strings of words1 are unique.

Code​

Python Code
class Solution:
     def wordSubsets(self, A, B):
        count = collections.Counter()
        for b in B:
            count |= collections.Counter(b)
        return [a for a in A if not count - Counter(a)]