JAVA 两句话中的不常见单词

class Solution {
    public String[] uncommonFromSentences(String A, String B) {
        List<String> list = new ArrayList<>();
        String[] split = A.split(" ");
        String[] split2 =B.split(" ");
        HashMap<String,Integer> map = new HashMap<>(); 
        for(String s:split) {
            map.put(s, map.getOrDefault(s, 0)+1);
        }
        for(String s2:split2) {
            map.put(s2,map.getOrDefault(s2, 0)+1);
        }
        for(Map.Entry<String, Integer> entry :map.entrySet()) {
            if(entry.getValue() == 1) {
                list.add(entry.getKey());
            }
        }
        
        return list.toArray(new String[list.size()]);
    }
}