# 1002. Find Common Characters 查找共用字符

@TOC

## # 题目描述

Given an array `A` of strings made only from lowercase letters, return a list of all characters that show up in all strings within the list (including duplicates). For example, if a character occurs 3 times in all strings but not 4 times, you need to include that character three times in the final answer.

You may return the answer in any order.

Example 1:

``````Input: ["bella","label","roller"]
Output: ["e","l","l"]
``````

Example 2:

``````Input: ["cool","lock","cook"]
Output: ["c","o"]
``````

Note:

1. `1 <= A.length <= 100`
2. `1 <= A[i].length <= 100`
3. `A[i][j]` is a lowercase letter

## # 解题方法

### # 字典

python代码如下：

``````class Solution(object):
def commonChars(self, A):
"""
:type A: List[str]
:rtype: List[str]
"""
A_count = map(lambda x : collections.Counter(x), A)
res = []
for i in range(26):
c = chr(ord('a') + i)
min_count = min([a_count[c] for a_count in A_count])
if min_count:
res.extend([c] * min_count)
return res
``````

## # 日期

2019 年 3 月 3 日 —— 3月开始，春天到了