Add solution #33

Author: JoshCrozier

README.md

@@ -29,6 +29,7 @@
 27|[Remove Element](./0027-remove-element.js)|Easy|
 28|[Implement strStr()](./0028-implement-strstr.js)|Easy|
 31|[Next Permutation](./0031-next-permutation.js)|Medium|
+33|[Search in Rotated Sorted Array](./0033-search-in-rotated-sorted-array.js)|Medium|
 36|[Valid Sudoku](./0036-valid-sudoku.js)|Medium|
 41|[First Missing Positive](./0041-first-missing-positive.js)|Hard|
 42|[Trapping Rain Water](./0042-trapping-rain-water.js)|Hard|

solutions/0033-search-in-rotated-sorted-array.js

@@ -0,0 +1,44 @@
+/**
+ * 33. Search in Rotated Sorted Array
+ * https://leetcode.com/problems/search-in-rotated-sorted-array/
+ * Difficulty: Medium
+ *
+ * There is an integer array nums sorted in ascending order (with distinct values).
+ *
+ * Prior to being passed to your function, nums is possibly rotated at an unknown pivot
+ * index k (1 <= k < nums.length) such that the resulting array is [nums[k], nums[k+1],
+ * ..., nums[n-1], nums[0], nums[1], ..., nums[k-1]] (0-indexed). For example, [0,1,2,4,5,6,7]
+ * might be rotated at pivot index 3 and become [4,5,6,7,0,1,2].
+ *
+ * Given the array nums after the possible rotation and an integer target, return the index
+ * of target if it is in nums, or -1 if it is not in nums.
+ *
+ * You must write an algorithm with O(log n) runtime complexity.
+ */
+
+/**
+ * @param {number[]} nums
+ * @param {number} target
+ * @return {number}
+ */
+var search = function(nums, target) {
+  let start = 0;
+  let end = nums.length;
+
+  while (start < end) {
+    const i = Math.floor((start + end) / 2);
+    const middle = nums[i] < nums[0] === target < nums[0]
+      ? nums[i]
+      : target < nums[0] ? -Infinity : Infinity;
+
+    if (middle < target) {
+      start = i + 1;
+    } else if (middle > target) {
+      end = i;
+    } else {
+      return i;
+    }
+  }
+
+  return -1;
+};