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 <= A.length <= 1001 <= A[i].length <= 100Ai is a lowercase letter

难度: easy

题目：给定字符串数组Ａ仅由小字符组成，返回所有在所有字符串中都出现过的字符，包括重复。例如，如果一个字符在所有字符串出现了3次而非4次，则返回结果中要包含3次。返回顺序不限。

思路：每个字符串一个统计表。

Runtime: 7 ms, faster than 100.00% of Java online submissions for Find Common Characters.Memory Usage: 38.1 MB, less than 100.00% of Java online submissions for Find Common Characters.

class Solution {    public List
    
      commonChars(String[] A) {        int n = A.length;        int[][] cc = new int[n][26];                for (int i = 0; i < n; i++) {            for (char c : A[i].toCharArray()) {                cc[i][c - 'a']++;            }        }                List
     
       result = new ArrayList<>();        for (int i = 0; i < 26; i++) {            int minCount = 100;            for (int j = 0; j < n; j++) {                minCount = Math.min(minCount, cc[j][i]);            }                        for (int j = 0; j < minCount; j++) {                result.add(String.valueOf((char) (i + 'a')));            }        }                return result;    }}