查找常用字符

给定仅有小写字母组成的字符串数组 A，返回列表中的每个字符串中都显示的全部字符（包括重复字符）组成的列表。例如，如果一个字符在每个字符串中出现 3 次，但不是 4 次，则需要在最终答案中包含该字符 3 次。

你可以按任意顺序返回答案。

 

示例 1：

输入：["bella","label","roller"]

输出：["e","l","l"]

示例 2：

输入：["cool","lock","cook"]

输出：["c","o"]

 

提示：

1 <= A.length <= 100

1 <= A[i].length <= 100

A[i][j] 是小写字母

来源：力扣（LeetCode）

链接：https://leetcode-cn.com/problems/find-common-characters

著作权归领扣网络所有。商业转载请联系官方授权，非商业转载请注明出处。

class Solution:    def commonChars(self, l: list) -> list:        appearance = {}        multi = []        for word in l:            appearance[word] = {}            for letter in set(word):                appearance[word][letter] = word.count(letter)        trial = l[0]        for letter in trial:            flag = True            for word, times in appearance.items():                if letter not in times or times[letter] == 0:                    flag = False                    break            if flag:                multi.append(letter)                for word, times in appearance.items():                    times[letter] -= 1        return multiif __name__ == '__main__':    print(Solution().commonChars(['bella', 'label', 'roller']))    print(Solution().commonChars(['cool', 'lock', 'cook']))