_916.cpp

class Solution {
public:
    vector<string> wordSubsets(vector<string>& words1, vector<string>& words2) {
        int maxCharFreq[26] = {0};
        int tempCharFreq[26];
        for (const auto& word : words2) {
            memset(tempCharFreq, 0, sizeof tempCharFreq);
            for (char ch : word) {
                tempCharFreq[ch - 'a']++;
            }
            for (int i = 0; i < 26; ++i) {
                maxCharFreq[i] = max(maxCharFreq[i], tempCharFreq[i]);
            }
        } 
        vector<string> universalWords;
        for (const auto& word : words1) {
            memset(tempCharFreq, 0, sizeof tempCharFreq);
            for (char ch : word) {
                tempCharFreq[ch - 'a']++;
            }
            bool isUniversal = true;
            for (int i = 0; i < 26; ++i) {
                if (maxCharFreq[i] > tempCharFreq[i]) {
                    isUniversal = false;
                    break;
                }
            }
            if (isUniversal) {
                universalWords.emplace_back(word);
            }
        }
        return universalWords;
    }
};