Add solution #29

Author: JoshCrozier

README.md

@@ -28,6 +28,7 @@
 24|[Swap Nodes in Pairs](./0024-swap-nodes-in-pairs.js)|Medium|
 27|[Remove Element](./0027-remove-element.js)|Easy|
 28|[Implement strStr()](./0028-implement-strstr.js)|Easy|
+29|[Divide Two Integers](./0029-divide-two-integers.js)|Medium|
 31|[Next Permutation](./0031-next-permutation.js)|Medium|
 33|[Search in Rotated Sorted Array](./0033-search-in-rotated-sorted-array.js)|Medium|
 34|[Find First and Last Position of Element in Sorted Array](./0034-find-first-and-last-position-of-element-in-sorted-array.js)|Medium|

solutions/0029-divide-two-integers.js

@@ -0,0 +1,46 @@
+/**
+ * 29. Divide Two Integers
+ * https://leetcode.com/problems/divide-two-integers/
+ * Difficulty: Medium
+ *
+ * Given two integers dividend and divisor, divide two integers without using multiplication,
+ * division, and mod operator.
+ *
+ * The integer division should truncate toward zero, which means losing its fractional part.
+ * For example, 8.345 would be truncated to 8, and -2.7335 would be truncated to -2.
+ *
+ * Return the quotient after dividing dividend by divisor.
+ *
+ * Note: Assume we are dealing with an environment that could only store integers within the
+ * 32-bit signed integer range: [−231, 231 − 1]. For this problem, if the quotient is strictly
+ * greater than 231 - 1, then return 231 - 1, and if the quotient is strictly less than -231,
+ * then return -231.
+ */
+
+/**
+ * @param {number} dividend
+ * @param {number} divisor
+ * @return {number}
+ */
+var divide = function(dividend, divisor) {
+  if (divisor === -1 && dividend === Math.pow(-2, 31)) {
+    return Math.pow(2, 31) - 1;
+  }
+  const isNegative = dividend > 0 ^ divisor > 0;
+  let result = 0;
+
+  dividend = Math.abs(dividend);
+  subtract(Math.abs(divisor), 1);
+
+  function subtract(n, quotient) {
+    if (dividend > n) {
+      subtract(n * 2, quotient * 2);
+    }
+    if (dividend >= n) {
+      dividend -= n;
+      result += quotient;
+    }
+  }
+
+  return isNegative ? -result : result;
+};