[leetcode]Maximum Product of Word Lengths

用了python的set。为了效率，先做了预处理，并排序了。要注意，排序完才好预处理，否则i，j会对不上。

 

class Solution:
    
    def maxProduct(self, words: List[str]) -> int:
        
        maxProd = 0
        
        words = sorted(words, key=lambda x:-len(x))
        
        charSets = []
        for i in range(len(words)):
            charSets.append(set(list(words[i])))
            
        for i in range(len(words)):
            for j in range(i + 1, len(words)):
                if len(charSets[i] & charSets[j]) == 0:
                    prod = len(words[i]) * len(words[j])
                    if prod > maxProd:
                        maxProd = prod
                    break
                    
        return maxProd