884.cpp

class Solution { // 0ms
public:
  vector<string> uncommonFromSentences(string A, string B) {
    unordered_map<string, int> count;
    istringstream iss(A + " " + B);
    while (iss >> A)
      count[A]++;
    vector<string> res;
    for (auto &w : count)
      if (w.second == 1)
        res.push_back(w.first);
    return res;
  }
};