import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
public class KeyBoardRow {
private static final Map alphabetPosition = new HashMap<>();
static {
alphabetPosition.put('Q', 1);
alphabetPosition.put('W', 1);
alphabetPosition.put('E', 1);
alphabetPosition.put('R', 1);
alphabetPosition.put('T', 1);
alphabetPosition.put('Y', 1);
alphabetPosition.put('U', 1);
alphabetPosition.put('I', 1);
alphabetPosition.put('O', 1);
alphabetPosition.put('P', 1);
alphabetPosition.put('A', 2);
alphabetPosition.put('S', 2);
alphabetPosition.put('D', 2);
alphabetPosition.put('F', 2);
alphabetPosition.put('G', 2);
alphabetPosition.put('H', 2);
alphabetPosition.put('J', 2);
alphabetPosition.put('K', 2);
alphabetPosition.put('L', 2);
alphabetPosition.put('Z', 3);
alphabetPosition.put('X', 3);
alphabetPosition.put('C', 3);
alphabetPosition.put('V', 3);
alphabetPosition.put('B', 3);
alphabetPosition.put('N', 3);
alphabetPosition.put('M', 3);
}
public static String[] findWords(String[] words) {
List result = new ArrayList<>();
for (String word : words) {
if (singleRowWord(word.toUpperCase())) {
result.add(word);
}
}
return arrayListToArray(result);
}
private static String[] arrayListToArray(List list) {
String[] result = new String[list.size()];
for (int index = 0 ; index < result.length ; index++) {
result[index] = list.get(index);
}
return result;
}
private static boolean singleRowWord(String word) {
int row = alphabetPosition.get(word.charAt(0));
for (int index = 1 ; index < word.length() ; index++) {
if (row != alphabetPosition.get(word.charAt(index))) {
return false;
}
}
return true;
}
}