Create 166._

166._

+### 166. Fraction to Recurring Decimal
+
+题目:
+<https://leetcode.com/problems/fraction-to-recurring-decima/>
+
+
+难度:
+
+Medium
+
+
+
+
+```python
+class Solution:
+    # @return a string
+    def fractionToDecimal(self, n, d):
+        res = ''
+        if n == 0: # zero numerator
+            return str(n)
+        if (n < 0) ^ (d < 0): # determine the sign
+            res += '-'
+        n = abs(n) # remove sign of operands
+        d = abs(d) 
+        res += str(n / d) # append integral part
+        if (n % d == 0): # in case no fractional part
+            return res
+        res += '.'
+        r = n % d
+        m = {}
+        while r: # simulate the division process
+            if r in m: # meet a known remainder
+                res = res[:m[r]] + '(' + res[m[r]:] + ')' # so we reach the end of the repeating part
+                break
+            m[r] = len(res) # if the remainder is first seen, remember the current position for it
+            r *= 10
+            res += str(r / d) # append the quotient digit
+            r %= d
+        return res
+```
+
+