1+ /*
2+ Author: King, wangjingui@outlook.com
3+ Date: Dec 15, 2014
4+ Problem: Fraction to Recurring Decimal
5+ Difficulty: Easy
6+ Source: https://oj.leetcode.com/problems/fraction-to-recurring-decimal/
7+ Notes:
8+ Given two integers representing the numerator and denominator of a fraction, return the fraction in string format.
9+
10+ If the fractional part is repeating, enclose the repeating part in parentheses.
11+
12+ For example,
13+
14+ Given numerator = 1, denominator = 2, return "0.5".
15+ Given numerator = 2, denominator = 1, return "2".
16+ Given numerator = 2, denominator = 3, return "0.(6)".
17+
18+ Solution: ...
19+ */
20+ public class Solution {
21+ public String fractionToDecimal (int numerator ,int denominator ) {
22+ if (numerator ==0 )return new String ("0" );
23+ boolean flag = (numerator <0 )^(denominator <0 );
24+ long Numerator =Math .abs ((long )numerator );
25+ long Denominator =Math .abs ((long )denominator );
26+ StringBuffer res =new StringBuffer ();
27+ if (flag ==true )res .append ('-' );
28+ res .append (String .valueOf ((Numerator /Denominator )));
29+ Numerator =Numerator %Denominator ;
30+ if (Numerator ==0 )return res .toString ();
31+ res .append ('.' );
32+ HashMap <Long ,Integer >map =new HashMap <Long ,Integer >();
33+ for (int i =res .length ();Numerator !=0 ; ++i ) {
34+ if (map .get (Numerator ) !=null )break ;
35+ map .put (Numerator ,i );
36+ Numerator *=10 ;
37+ res .append (String .valueOf ((Numerator /Denominator )));
38+ Numerator %=Denominator ;
39+ }
40+
41+ if (Numerator ==0 )return res .toString ();
42+ res .insert (map .get (Numerator ),"(" );
43+ res .append (')' );
44+ return res .toString ();
45+ }
46+ }
