public String fractionToDecimal(int numerator, int denominator) {

boolean sameSign = (numerator >= 0 && denominator >= 0) || (numerator < 0 && denominator < 0);

long nume = Math.abs((long)numerator);

long deno = Math.abs((long)denominator);

Long ones = nume / deno;

List<Long> decimals = new ArrayList<>();

long left = nume % deno;

Map<Long, Integer> map = new HashMap<>();

left *= 10;

int pos = 0;

int repeat = -1;

while (true) {

if (left == 0) break;

if (map.containsKey(left)) {

repeat = map.get(left);

break;

}

long newOne = Math.abs(left / deno);

long newLeft = left % deno;

decimals.add(newOne);

map.put(left, pos);

left = newLeft*10;

pos++;

}

String pre = (sameSign || ones <= 0L) ? ones.toString() : ("-" + ones.toString());

if (decimals.size() == 0) return pre;

StringBuilder sb = new StringBuilder();

for (int i=0; i<decimals.size(); i++) {

String curr = decimals.get(i).toString();

String newD = (repeat != i) ? curr : ("(" + curr);

sb.append(newD);

}

if (repeat != -1) sb.append(")");

return String.format("%s.%s", (sameSign) ? ones.toString() : ("-" + ones.toString()), sb);

}

public String fractionToDecimal2(int numerator, int denominator) {

if (numerator == 0) {

return "0";

}

StringBuilder fraction = new StringBuilder();

if (numerator < 0 ^ denominator < 0) {

fraction.append("-");

}

long num = Math.abs(Long.valueOf(numerator));

long denom = Math.abs(Long.valueOf(denominator));

fraction.append(num / denom);

long remainder = num % denom;

if (remainder == 0) {

return fraction.toString();

}

fraction.append(".");

HashMap<Long, Integer> map = new HashMap<>();

while (remainder != 0) {

if (map.containsKey(remainder)) {

fraction.insert(map.get(remainder), "(");

fraction.append(")");

break;

}

map.put(remainder, fraction.length());

remainder *= 10;

fraction.append(remainder / denom);

remainder = remainder % denom;

}

return fraction.toString();

}