884. Uncommon Words from Two Sentences

Q:

We are given two sentences A and B.  (A sentence is a string of space separated words.  Each word consists only of lowercase letters.)

A word is uncommon if it appears exactly once in one of the sentences, and does not appear in the other sentence.

Return a list of all uncommon words. 

You may return the list in any order.

 

Example 1:

Input: A = "this apple is sweet", B = "this apple is sour"
Output: ["sweet","sour"]

Example 2:

Input: A = "apple apple", B = "banana"
Output: ["banana"]

 

Note:

1. 0 <= A.length <= 200
2. 0 <= B.length <= 200
3. A and B both contain only spaces and lowercase letters.

A:

class Solution {
public:
    vector<string> uncommonFromSentences(string A, string B) {
        istringstream iss(A);
        vector<string> strA(istream_iterator<string>{iss},istream_iterator<string>());
        istringstream iss2(B);
        vector<string> strB(istream_iterator<string>{iss2},istream_iterator<string>());
        
        unordered_map<string, int > S1;
        for(auto & s : strA){
            S1[s] +=1;
        }
        unordered_map<string, int > S2;
        for(auto & s : strB){
            S2[s] +=1;
        }
        vector<string> res;
        for(auto & s : strA){
            if(S1[s] == 1 && S2.find(s)==S2.end())
            {
                res.push_back(s);
                // cout << s << endl;
            }
        }
        for(auto & s : strB)
            if(S2[s] == 1 && S1.find(s)==S1.end())
                res.push_back(s);
        
        return res;
    }
};

一开始题意没有看清楚，  if it appears exactly once in one of the sentences

Learned:    how to split string via space in C++

        istringstream iss(A);
        vector<string> strA(istream_iterator<string>{iss},istream_iterator<string>());