Merge pull request ignacio-chiazzo#12 from ignacio-chiazzo/search-rotated

Added search rotated

Author: ignacio-chiazzo

LeetcodeProblems/SearchInRotatedSortedArray.js

@@ -0,0 +1,54 @@
+/* 
+33. Search in Rotated Sorted Array
+DescriptionHintsSubmissionsDiscussSolution
+Suppose an array sorted in ascending order is rotated at some pivot unknown to you beforehand.
+
+(i.e., [0,1,2,4,5,6,7] might become [4,5,6,7,0,1,2]).
+
+You are given a target value to search. If found in the array return its index, otherwise return -1.
+
+You may assume no duplicate exists in the array.
+
+Your algorithm's runtime complexity must be in the order of O(log n).
+
+Example 1:
+
+Input: nums = [4,5,6,7,0,1,2], target = 0
+Output: 4
+Example 2:
+
+Input: nums = [4,5,6,7,0,1,2], target = 3
+Output: -1
+
+*/
+
+/**
+ * @param {number[]} nums
+ * @param {number} target
+ * @return {number}
+ */
+var search = function(nums, target) {
+  return searchAux(nums, target, 0, nums.length -1);
+};
+
+var searchAux = function(nums, target, start, end) {
+  if (start > end)
+    return - 1;
+  var middle =  Math.trunc((start + end) /2);
+  
+  if(nums[middle] == target) {
+    return middle;
+  }
+  
+  if(nums[middle] < nums[nums.length - 1]) { // right part sorted
+    if(nums[middle] < target && nums[nums.length - 1] >= target) {
+      return searchAux(nums, target, middle + 1, end);
+    }
+    return searchAux(nums, target, start, middle - 1);
+  } else { // left part sorted
+    if(nums[0] <= target && nums[middle] > target) {
+      return searchAux(nums, target, start, middle - 1);
+    }
+    return searchAux(nums, target, middle + 1, end);
+  }
+}