vector<string> wordSubsets(vector<string>& A, vector<string>& B) {

int n = (int)A.size();

unordered_map<int, int> freqMap[n];

for (int i = 0; i < n; i++) {

for (int j = 0; j < (int)A[i].length(); j++) {

freqMap[i][A[i][j]] ++;

}

}

unordered_map<int, int> maxFreqMap;

for (string& s : B) {

unordered_map <int, int> freqMap;

for (int i = 0; i < s.length(); i++) {

freqMap[s[i]] ++;

}

for(auto entry : freqMap) {

maxFreqMap[entry.first] = max(maxFreqMap[entry.first], entry.second);

}

}

vector<string> result;

for(int i = 0; i < n; i++) {

bool isUniversal = true;

for(auto entry : maxFreqMap) {

if(freqMap[i][entry.first] < entry.second) {

isUniversal = false;

break;

}

}

if(isUniversal) {

result.push_back(A[i]);

}

}

return result;

}