集合的优势（leetcode 318 python）

给定一个字符串数组 words，找到 length(word[i]) * length(word[j]) 的最大值，并且这两个单词不含有公共字母。你可以认为每个单词只包含小写字母。如果不存在这样的两个单词，返回 0。

示例 1:

输入: ["abcw","baz","foo","bar","xtfn","abcdef"]
输出: 16 
解释: 这两个单词为 "abcw", "xtfn"。

示例 2:

输入: ["a","ab","abc","d","cd","bcd","abcd"]
输出: 4 
解释: 这两个单词为 "ab", "cd"。

示例 3:

输入: ["a","aa","aaa","aaaa"]
输出: 0 
解释: 不存在这样的两个单词。

class Solution(object):
    def maxProduct(self, words):
        """
        :type words: List[str]
        :rtype: int
        """
        m = 0
        dic = {}
        for word in words:
            dic[word] = set(word)
        for i in range(len(words)):
            for j in range(i + 1, len(words)):
                if len(words[i]) * len(words[j]) > m and len(dic[words[i]] & dic[words[j]]) == 0:
                    m = len(words[i]) * len(words[j])
        return m