class Solution {
    public String[] findWords(String[] words) {
        String row1="QWERTYUIOPqwertyuiop";
        String row2="ASDFGHJKLasdfghjkl";
        String row3="ZXCVBNMzxcvbnm";
        List<String> list = new ArrayList<>();
        for(String word:words){
            int[][] counter = new int[1][3];
            for(int i=0; i<word.length(); i++){
                if(row1.contains(word.valueOf(word.charAt(i))))
                    counter[0][0]++;
                if(row2.contains(word.valueOf(word.charAt(i))))
                    counter[0][1]++;
                if(row3.contains(word.valueOf(word.charAt(i))))
                    counter[0][2]++;
            }
            if(counter[0][0]==word.length()||counter[0][1]==word.length()||counter[0][2]==word.length()) list.add(word);
        }
        return list.toArray(new String[0]);
    }
}