Leetcode 166:fraction to recurring Decimal

Fraction to recurring DecimalTotal Accepted: 3168 Total Submissions: 27432

Given integers representing the numerator and denominator of a fraction, return the fraction in string format.

If the fractional part was 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) ".

Analysis

The key is to determine where the loop takes place, using the map to store all the remainder, and a loop occurs when the remainder is already obsolete.

Note

Overflow, the processing of symbols, separate two functions, make the code easier to read

[CODE]

public class Solution {public String fractiontodecimal (int numerator, int denominator) {Long num = num        Erator;        Long den = denominator;        Boolean neg = num * den < 0;        num = Math.Abs (num);        Den = Math.Abs (DEN); String res = neg?        "-" + long.tostring (Num/den): long.tostring (Num/den);                long remainder = Num%den; Return (remainder==0)?            Res: (res + "." + getdec (remainder, den)); } private StringBuilder Getdec (long remainder, long den) {map<long, integer> Map = new Hashmap<lon        G, integer> ();        int i=0;        StringBuilder sb = new StringBuilder ();        while (remainder!=0 &&!map.containskey (remainder)) {map.put (remainder, i);        ++i;        Remainder *= 10;        Sb.append (long.tostring (Remainder/den));        Remainder%= den;            } if (remainder!=0) {Sb.insert ((int) map.get (remainder), ' (');      Sb.append (') ');  } return SB; }}

Leetcode 166:fraction to recurring Decimal