Java simple solution using HashMap, beats 90%!
\nclass Solution {\n    public String[] uncommonFromSentences(String A, String B) {\n\tString C = A+ " " + B;\n\tHashMap<String, Integer> map = new HashMap<>();
```\nclass Solution {\n    public String[] uncommonFromSentences(String A, String B) {\n\tString C = A+ " " + B;\n\tHashMap<String, Integer> map = new HashMap<>();\n\tfor(String word: C.split(" ")) map.put(word, map.getOrDefault(word, 0)+1);\n\tIterator<Map.Entry<String, Integer>> it = map.entrySet().iterator();\n\twhile(it.hasNext()){\n\t\tMap.Entry<String, Integer> entry = it.next();\n\t\tif(entry.getValue() > 1){\n\t\t\tit.remove();\n\t\t}\n\t}\n\treturn map.keySet().toArray(new String[0]);\n    }\n}\n```
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