_1271.java

packagecom.fishercoder.solutions.secondthousand;

importjava.util.Arrays;
importjava.util.HashSet;
importjava.util.Set;

publicclass_1271 {
publicstaticclassSolution1 {
publicStringtoHexspeak(Stringnum) {
longnumInt = Long.parseLong(num);
StringhexString = Long.toHexString(numInt);
StringBuildersb = newStringBuilder();
Set<Character> set =
newHashSet<>(
Arrays.asList(
'A', 'B', 'C', 'D', 'E', 'F', '1', '0', 'a', 'b', 'c', 'd', 'e',
'f'));
for (charc : hexString.toCharArray()) {
if (!set.contains(c)) {
return"ERROR";
 } elseif (c == '1') {
sb.append("I");
 } elseif (c == '0') {
sb.append("O");
 } else {
sb.append(Character.toUpperCase(c));
 }
 }
returnsb.toString();
 }
 }
}