Given two integers representing the numerator and denominator of a fraction, return the fraction in string format.
If the fractional part is repeating, enclose the repeating part in parentheses.
For example,
- Given numerator = 1, denominator = 2, return "0.5".
- Given numerator = 2, denominator = 1, return "2".
- Given numerator = 2, denominator = 3, return "0.(6)".
题目含义：计算两个数的除法，出现无限循环位置时，用括号括起来
1 public String fractionToDecimal(int numerator, int denominator) { 2 if (denominator ==0) return ""; 3 StringBuilder result = new StringBuilder(); 4 String sign = (numerator < 0 == denominator < 0 || numerator == 0) ? "" : "-"; 5 long num = Math.abs((long) numerator); 6 long den = Math.abs((long) denominator); 7 result.append(sign); 8 result.append(num / den); 9 long remainder = num % den; 10 if (remainder == 0) 11 return result.toString(); 12 result.append("."); 13 HashMap<Long, Integer> hashMap = new HashMap<Long, Integer>(); 14 while (!hashMap.containsKey(remainder)) { 15 hashMap.put(remainder, result.length()); 16 result.append(10 * remainder / den); 17 remainder = 10 * remainder % den; 18 } 19 int index = hashMap.get(remainder); 20 result.insert(index, "("); 21 result.append(")"); 22 return result.toString().replace("(0)", ""); 23 }