We are given two sentencesAandB. (Asentence is a string of space separated words. Each_word_consists only of lowercase letters.)

A word isuncommon 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.

Note:

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

这道题也没啥意思，按照要求来

class Solution {
    public String[] uncommonFromSentences(String A, String B) {
        HashMap<String, Boolean> mapA = new HashMap<>();
        HashMap<String, Boolean> mapB = new HashMap<>();

        List<String> list = new ArrayList<String>();
        int i = 0;
        while(i < A.length()) {
            while(i < A.length() && A.charAt(i) == ' ')
                i++;
            int j = i;
            while(j < A.length() && A.charAt(j) != ' ')
                j++;

            String word = A.substring(i, j);
            if(mapA.containsKey(word))
                mapA.put(word, false);
            else
                mapA.put(word, true);
            i = j;
        }

        i = 0;
        while(i < B.length()) {
            while(i < B.length() && B.charAt(i) == ' ')
                i++;
            int j = i;
            while(j < B.length() && B.charAt(j) != ' ')
                j++;

            String word = B.substring(i, j);
            if(mapB.containsKey(word))
                mapB.put(word, false);
            else
                mapB.put(word, true);
            i = j;
        }

        for(Map.Entry<String, Boolean> entry: mapA.entrySet()) {
            if(!entry.getValue())
                continue;

            if(!mapB.containsKey(entry.getKey()))
                list.add(entry.getKey());
        }
        for(Map.Entry<String, Boolean> entry: mapB.entrySet()) {
            if(!entry.getValue())
                continue;

            if(!mapA.containsKey(entry.getKey()))
                list.add(entry.getKey());
        }

        String[] res = new String[list.size()];
        for(i = 0; i < res.length; i++)
            res[i] = list.get(i);

        return res;
    }
}