Add solution #166

Author: JoshCrozier

README.md

@@ -152,6 +152,7 @@
 162|[Find Peak Element](./0162-find-peak-element.js)|Medium|
 164|[Maximum Gap](./0164-maximum-gap.js)|Medium|
 165|[Compare Version Numbers](./0165-compare-version-numbers.js)|Medium|
+166|[Fraction to Recurring Decimal](./0166-fraction-to-recurring-decimal.js)|Medium|
 167|[Two Sum II - Input Array Is Sorted](./0167-two-sum-ii-input-array-is-sorted.js)|Easy|
 168|[Excel Sheet Column Title](./0168-excel-sheet-column-title.js)|Easy|
 169|[Majority Element](./0169-majority-element.js)|Easy|

solutions/0166-fraction-to-recurring-decimal.js

@@ -0,0 +1,51 @@
+/**
+ * 166. Fraction to Recurring Decimal
+ * https://leetcode.com/problems/fraction-to-recurring-decimal/
+ * Difficulty: Medium
+ *
+ * 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.
+ *
+ * If multiple answers are possible, return any of them.
+ *
+ * It is guaranteed that the length of the answer string is less than 104 for all the
+ * given inputs.
+ */
+
+/**
+ * @param {number} numerator
+ * @param {number} denominator
+ * @return {string}
+ */
+var fractionToDecimal = function(numerator, denominator) {
+  if (numerator === 0) return '0';
+
+  const map = new Map();
+  let result = '';
+
+  if (Math.sign(numerator) !== Math.sign(denominator)) {
+    result += '-';
+  }
+
+  numerator = Math.abs(numerator);
+  denominator = Math.abs(denominator);
+  result += Math.floor(numerator / denominator);
+
+  let remainder = numerator % denominator;
+  while (remainder) {
+    result = result.indexOf('.') === -1 ? `${result}.` : result;
+    if (map.has(remainder)) {
+      const index = map.get(remainder);
+      result = `${result.slice(0, index)}(${result.slice(index)})`;
+      break;
+    }
+    map.set(remainder, result.length);
+    remainder *= 10;
+    result += Math.floor(remainder / denominator);
+    remainder %= denominator;
+  }
+
+  return result;
+};