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)".
这题很麻烦。
1。首先要判断符号， numberator 和 denominator 都是可正可负的。
2。numberator 要用long 否则会溢出。
3。每一次只能被减数*10，而且当没有出现小数点前，不会出现括号。所以先把整数部分和小数点全部输出，
1 public class Solution { 2 public String fractionToDecimal(int numerator, int denominator) { 3 if(numerator == 0) return new String("0"); 4 StringBuilder sb = new StringBuilder(); 5 boolean o = (numerator < 0) ^ (denominator < 0); 6 if(o) sb.append("-"); 7 long a = Math.abs((long)numerator); 8 long b = Math.abs((long)denominator); 9 sb.append(String.valueOf(a / b)); 10 a = a % b; 11 if(a == 0) return sb.toString(); 12 sb.append("."); 13 HashMap<Long, Integer> map = new HashMap<Long, Integer>(); 14 for(int pos = sb.length(); a != 0; pos ++){ 15 a *= 10; 16 if(map.containsKey(a)){ 17 sb.insert(map.get(a), "("); 18 sb.append(")"); 19 break; 20 } 21 sb.append((int)(a / b)); 22 map.put(a, pos); 23 a = a % b; 24 } 25 return sb.toString(); 26 } 27 }