# LeetCode – Fraction to Recurring Decimal (Java)

Problem

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)".
```

Java Solution

See internal comments in the code.

```public String fractionToDecimal(int numerator, int denominator) { if (numerator == 0) return "0"; if (denominator == 0) return "";   String result = "";   // is result is negative if ((numerator < 0) ^ (denominator < 0)) { result += "-"; }   // convert int to long long num = numerator, den = denominator; num = Math.abs(num); den = Math.abs(den);   // quotient long res = num / den; result += String.valueOf(res);   // if remainder is 0, return result long remainder = (num % den) * 10; if (remainder == 0) return result;   // right-hand side of decimal point HashMap<Long, Integer> map = new HashMap<Long, Integer>(); result += "."; while (remainder != 0) { // if digits repeat if (map.containsKey(remainder)) { int beg = map.get(remainder); String part1 = result.substring(0, beg); String part2 = result.substring(beg, result.length()); result = part1 + "(" + part2 + ")"; return result; }   // continue map.put(remainder, result.length()); res = remainder / den; result += String.valueOf(res); remainder = (remainder % den) * 10; }   return result; }```
Category >> Algorithms >> Interview >> Java
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• zerozero nine
• Saurabh Singh Rajput

``` import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; import java.util.HashMap; import java.util.StringTokenizer;```

``` public class A_Simple_Fraction { static class MyReader { BufferedReader input = null; StringTokenizer st = null; public MyReader() { input = new BufferedReader(new InputStreamReader(System.in)); } Integer nextInt() { return Integer.parseInt(next()); } Long nextLong() { return Long.parseLong(next()); } String next() { while (st == null || !st.hasMoreTokens()) { try { st = new StringTokenizer(input.readLine().trim()); } catch (IOException e) { e.printStackTrace(); } } return st.nextToken(); } } public static void main(String[] args) { MyReader input = new MyReader(); int testCase = input.nextInt(); while (testCase-- > 0) { int n = input.nextInt(); int d = input.nextInt(); doSimpleFraction(n, d); System.out.println(); } } private static void doSimpleFraction(int n, int d) { StringBuilder sb = new StringBuilder(""); StringBuilder afterDecimmal = new StringBuilder(""); HashMap mods = new HashMap(); boolean isInfinite = true; int beforeDec = n / d; int reminder = n % d; int charPos = 0; sb.append(beforeDec); if (reminder == 0) { System.out.print(sb); return; } while (!mods.containsKey(reminder) && reminder != 0) { mods.put(reminder, charPos++); int newN = reminder * 10; if (newN != 0) { afterDecimmal.append(newN / d); } reminder = newN % d; if (reminder == 0) { isInfinite = false; } } if (isInfinite) { int pos = mods.get(reminder); String s1 = "." + afterDecimmal.substring(0, pos); String s2 = afterDecimmal.substring(pos); System.out.print(sb + s1 + "(" + s2 + ")"); } else { System.out.print(sb + "." + afterDecimmal); } } } ```

• Gaurang Bhatt

This solution would fail for the fraction 667/10000 because it assumes the first repeating number will continue to repeat.

• Sreeparna Mukherjee

Time limit is getting exceeded in the above code.

``` long nume = Math.abs((long)numerator); long deno = Math.abs((long)denominator); String sign = (numerator < 0) ^ (denominator < 0) ? "-" : ""; if (deno == 0) { return ""; } else if (nume == 0) { return "0"; } else if (nume % deno == 0) { return sign + nume/deno + ""; } HashMap map = new HashMap(); StringBuffer rst = new StringBuffer(sign + nume/deno + "."); long end = nume%deno * 10;//The decimal portion of the value, after decimal point int i = 0; while (end != 0){ if (map.containsKey(end)) { rst.insert(rst.indexOf(".") + map.get(end) + 1, "("); rst.append(")"); return rst.toString(); } rst.append(end/deno); map.put(end, i++); end = (end % deno) * 10; } return rst.toString(); } } ```