static int lonelyInteger(int[] arr) {
Map<Integer, Integer> occurrences = new HashMap<>();
for (int value : arr) {
boolean alreadyExist = occurrences.containsKey(value);
if (!alreadyExist) {
occurrences.put(value, 0);
}
occurrences.put(value, occurrences.get(value) + 1);
}
int result = 0;
for (java.util.Map.Entry<Integer, Integer> entry : occurrences.entrySet()) {
if (entry.getValue().equals(1)) {
result = entry.getKey();
}
}
return result;
}
/**
* This method gets called when we're testing a dictionary object against some type. To reduce the
* number of cases, we can narrow down the possible types by a process of deduction. The type
* cannot be <code>void</code> or <code>any</code> (since the test would already have been
* eliminated). Likewise, it cannot be e.g. a record, since again the test would already have been
* eliminated. In fact, the type can only be a dictionary or its negation.
*
* @param object --- object being tested against.
* @param type --- type to test against.
* @return
*/
public static boolean instanceOf(Dictionary object, Type type) {
if (type instanceof Type.Dictionary) {
Type.Dictionary tl = (Type.Dictionary) type;
Type key = tl.key;
Type value = tl.value;
if (key.kind == K_ANY && value.kind == K_ANY) {
return true;
} else if (key.kind == K_VOID || value.kind == K_VOID) {
return object.isEmpty();
} else {
for (java.util.Map.Entry<Object, Object> elem : object.entrySet()) {
if (!instanceOf(elem.getKey(), key) || !instanceOf(elem.getValue(), value)) {
return false;
}
}
return true;
}
} else {
return instanceOf((Object) object, type);
}
}
/** The <code>instanceOf</code> method implements a runtime type test. */
public static boolean instanceOf(Object obj, Type t) {
switch (t.kind) {
case K_ANY:
return true;
case K_VOID:
return false;
case K_NULL:
return obj == null;
case K_BOOL:
return obj instanceof Boolean;
case K_BYTE:
return obj instanceof Byte;
case K_CHAR:
return obj instanceof Character;
case K_INT:
return obj instanceof BigInteger;
case K_RATIONAL:
return obj instanceof BigRational;
case K_STRING:
return obj instanceof String;
case K_LIST:
{
if (obj instanceof List) {
List ol = (List) obj;
Type.List tl = (Type.List) t;
if (tl.nonEmpty && ol.isEmpty()) {
return false;
}
Type el = tl.element;
if (el.kind == K_ANY) {
return true;
} else if (el.kind == K_VOID) {
return ol.isEmpty();
} else {
for (Object elem : ol) {
if (!instanceOf(elem, el)) {
return false;
}
}
return true;
}
}
break;
}
case K_SET:
{
if (obj instanceof Set) {
Set ol = (Set) obj;
Type.Set tl = (Type.Set) t;
Type el = tl.element;
if (el.kind == K_ANY) {
return true;
} else if (el.kind == K_VOID) {
return ol.isEmpty();
} else {
for (Object elem : ol) {
if (!instanceOf(elem, el)) {
return false;
}
}
return true;
}
}
break;
}
case K_TUPLE:
{
if (obj instanceof Tuple) {
Tuple ol = (Tuple) obj;
Type.Tuple tl = (Type.Tuple) t;
Type[] types = tl.types;
if (types.length == ol.size()) {
int i = 0;
for (Object o : ol) {
if (!instanceOf(o, types[i++])) {
return false;
}
}
return true;
}
}
break;
}
case K_DICTIONARY:
{
if (obj instanceof Dictionary) {
Dictionary ol = (Dictionary) obj;
Type.Dictionary tl = (Type.Dictionary) t;
Type key = tl.key;
Type value = tl.value;
if (key.kind == K_ANY && value.kind == K_ANY) {
return true;
} else if (key.kind == K_VOID || value.kind == K_VOID) {
return ol.isEmpty();
} else {
for (java.util.Map.Entry<Object, Object> elem : ol.entrySet()) {
if (!instanceOf(elem.getKey(), key) || !instanceOf(elem.getValue(), value)) {
return false;
}
}
return true;
}
}
break;
}
case K_RECORD:
{
if (obj instanceof Record) {
Record ol = (Record) obj;
Type.Record tl = (Type.Record) t;
String[] names = tl.names;
Type[] types = tl.types;
if (!tl.isOpen && names.length != ol.size()) {
return false;
}
for (int i = 0; i != names.length; ++i) {
String name = names[i];
if (ol.containsKey(name)) {
Type type = types[i];
Object val = ol.get(name);
if (!instanceOf(val, type)) {
return false;
}
} else {
return false;
}
}
return true;
}
break;
}
case K_NEGATION:
{
Type.Negation not = (Type.Negation) t;
return !instanceOf(obj, not.element);
}
case K_UNION:
{
Type.Union un = (Type.Union) t;
for (Type bound : un.bounds) {
if (instanceOf(obj, bound)) {
return true;
}
}
break;
}
}
return false;
}