一、题目

Given a string array words, return an array of all characters that show up in all strings within the words (including duplicates). You may return the answer in any order.

Example 1:

Input: words = [“bella”,“label”,“roller”]
Output: [“e”,“l”,“l”]
Example 2:

Input: words = [“cool”,“lock”,“cook”]
Output: [“c”,“o”]

Constraints:

1 <= words.length <= 100
1 <= words[i].length <= 100
words[i] consists of lowercase English letters.

二、题解

class Solution {
public:vector<string> commonChars(vector<string>& words) {int n = words.size();vector<int> hash(26,0);vector<int> hash1(26,0);vector<string> res;for(int i = 0;i < words[0].size();i++){hash[words[0][i] - 'a']++;}for(int i = 1;i < n;i++){for(int h = 0;h < 26;h++) hash1[h] = 0;string s = words[i];for(int j = 0;j < s.size();j++){hash1[s[j] - 'a']++;}//更新hashfor(int k = 0;k < 26;k++){hash[k] = min(hash[k],hash1[k]);}}for(int i = 0;i < 26;i++){while(hash[i] != 0){res.push_back(string(1,'a' + i));hash[i]--;}}return res;}
};