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.
Input: A = "this apple is sweet", B = "this apple is sour"
Input: A = "apple apple", B = "banana"
0 <= A.length <= 200
0 <= B.length <= 200
A and B both contain only spaces and lowercase letters.
unordered_map<string, int> mapp;
A = A + " " + B;
while(str >> s) ++mapp[s];
if(m.second == 1)