916. Word Subsets

We are given two arrays A and B of words. Each word is a string of lowercase letters.

Now, say that word b is a subset of word a if every letter in b occurs in a, including multiplicity. For example, “wrr” is a subset of “warrior”, but is not a subset of “world”.

Now say a word a from A is universal if for every b in B, b is a subset of a.

Return a list of all universal words in A. You can return the words in any order.

class Solution {
    bool chk(unordered_map<char, int>& a, unordered_map<char,int>& b) {
        for(auto entity : b) {
            if(a[entity.first] < entity.second)
                return false;
        }

        return true;
    }
public:
    vector<string> wordSubsets(vector<string>& A, vector<string>& B) {
        int bsz = B.size();
        vector<string> res;
        unordered_map<char, int> bMap;
        for(int i = 0; i < bsz; i++) {
            unordered_map<char,int> m;
            for(int j = 0; j < B[i].length(); j++)
                m[B[i][j]]++;
            for(auto entity : m) {
                bMap[entity.first] = max(bMap[entity.first], entity.second);
            }
        }

        for(string& a : A) {
            unordered_map<char,int> m;
            for(int i = 0; i < a.length(); i++)
                m[a[i]]++;
            if(chk(m, bMap))
                res.push_back(a);
        }

        return res;
    }
};

class Solution {
    public List<String> wordSubsets(String[] A, String[] B) {
        Map<Character, Integer> bMap = new HashMap<>();
        for (String b : B) {
            bMap = Stream.concat(bMap.entrySet().stream(),
                    b.chars().boxed().collect(Collectors.toMap(k -> (char) k.intValue(), v -> 1, Integer::sum))
                            .entrySet().stream())
                    .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue, (v1, v2) -> v1 > v2 ? v1 : v2, HashMap::new));
        }

        Map<Character, Integer> finalBMap = bMap;
        return Arrays.asList(A).parallelStream().filter(
                a -> {
                    Map<Character, Integer> aMap = a.chars().boxed().collect(Collectors.toMap(k -> (char) k.intValue(), v -> 1, Integer::sum));

                    for(Map.Entry<Character, Integer> entry : finalBMap.entrySet()) {
                        if(aMap.getOrDefault(entry.getKey(), 0) < entry.getValue())
                            return false;
                    }
                    return true;
                }
        ).collect(Collectors.toList());
    }
}