318. Maximum Product of Word Lengths

Problem Link

Description

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Given a string array words, return the maximum value of length(word[i]) * length(word[j]) where the two words do not share common letters. If no such two words exist, return 0.

 

Example 1:

Input: words = ["abcw","baz","foo","bar","xtfn","abcdef"]
Output: 16
Explanation: The two words can be "abcw", "xtfn".

Example 2:

Input: words = ["a","ab","abc","d","cd","bcd","abcd"]
Output: 4
Explanation: The two words can be "ab", "cd".

Example 3:

Input: words = ["a","aa","aaa","aaaa"]
Output: 0
Explanation: No such pair of words.

 

Constraints:

• 2 <= words.length <= 1000
• 1 <= words[i].length <= 1000
• words[i] consists only of lowercase English letters.

Solution

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Python3

class Solution:
    def maxProduct(self, words: List[str]) -> int:
        
        def getMask(word):
            mask = 0
            
            for x in word:
                mask |= (1 << (ord(x) - ord('a')))
            
            return mask
        
        masks = [getMask(word) for word in words]
        
        n = len(words)
        res = 0
        
        for i in range(n):
            for j in range(i + 1, n):
                if masks[i] & masks[j] == 0:
                    res = max(res, len(words[i]) * len(words[j]))
        
        return res