166_Fraction_to_Recurring_Decimal.java

classSolution {
publicStringfractionToDecimal(intnumerator, intdenominator) {
if (numerator == 0) {
return"0";
 }

StringBuilderresult = newStringBuilder();

if (numerator < 0 && denominator > 0 || numerator > 0 && denominator < 0) {
result.append("-");
 }

longdividend = Math.abs((long) numerator);
longdivisor = Math.abs((long) denominator);
longremainder = dividend % divisor;

result.append(dividend / divisor);

if (remainder == 0) {
returnresult.toString();
 }

result.append(".");

Map<Long, Integer> map = newHashMap<>();
while (remainder != 0) {
if (map.containsKey(remainder)) {
result.insert(map.get(remainder), "(");
result.append(")");
break;
 }

map.put(remainder, result.length());
remainder *= 10;
result.append(remainder / divisor);
remainder %= divisor;
 }

returnresult.toString();
 }
}