[LintCode] Longest Words

 ArrayList<String> longestWords(String[] dictionary) {
        // write your code here
        ArrayList<String> res = new ArrayList<String>();
        if(dictionary == null || dictionary.length == 0)
            return res;
        int len = dictionary[0].length();
        for(int i = 0; i < dictionary.length; i++) {
            if(dictionary[i].length() == len)
                res.add(dictionary[i]);
            else if(dictionary[i].length() > len){
                len = dictionary[i].length();
                res.clear();
                res.add(dictionary[i]);
            }
        }
        return res;
    }