Uncommon_words_with_two_sentences

class Solution {
    public String[] uncommonFromSentences(String s1, String s2) {
        String[] s1Split = s1.split(" ");
        String[] s2Split = s2.split(" ");
        HashMap<String, Integer> map = new HashMap<String,Integer>();
        for(String a : s1Split){
            map.put(a, map.getOrDefault(a,0)+1);
        }
        for(String a : s2Split){
            map.put(a, map.getOrDefault(a,0)+1);
        }
        List<String> res = new ArrayList<>();
        for(String a : map.keySet()){
            if(map.get(a) == 1)
            res.add(a);
        }
        return res.toArray(new String[0]);
    }
}