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Search in Rotated Sorted Array

Certification: Intermediate Level Accuracy: 0% Submissions: 0 Points: 10

Write a JavaScript function to search for a target value in a rotated sorted array without using any built-in search methods. A rotated sorted array is a sorted array that has been rotated at some pivot point. The function should return the index of the target if found, or -1 if not found. The solution should be efficient with O(log n) time complexity.

Example 1
    
      
  • Input: nums = [4, 5, 6, 7, 0, 1, 2], target = 0
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  • Output: 4
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  • Explanation: 
    • The array is rotated at index 4 (original: [0,1,2,4,5,6,7]). 
    • We need to find the target value 0. 
    • Using binary search, we identify which half contains the target. 
    • The target 0 is found at index 4. Return the index 4.
    •
Example 2
    
      
  • Input: nums = [4, 5, 6, 7, 0, 1, 2], target = 3
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  • Output: -1
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  • Explanation: 
    • The array is rotated and we're searching for target 3. 
    • Using binary search, we check both halves of the array. 
    • The left half [4,5,6,7] doesn't contain 3. 
    • The right half [0,1,2] doesn't contain 3. 
    • Since 3 is not found in the array, return -1.
    •
Constraints
    
      
  • All values in the array are unique
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  • The array was originally sorted in ascending order
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  • The array has been rotated at some pivot point
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  • You cannot use built-in search methods like indexOf() or find()
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  • Time Complexity: O(log n)
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  • Space Complexity: O(1)
    •
ArraysAlgorithmsGoldman SachsSamsung
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Solution

Solution Hints

    
      
  • Use binary search approach to achieve O(log n) time complexity
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  • Identify which half of the array is sorted at each step
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  • Check if the target lies within the sorted half
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  • Adjust the search boundaries based on the sorted half
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  • Handle the rotation by comparing with the middle element
    •

Steps to solve by this approach:

 Step 1: Initialize left and right pointers for binary search.
 Step 2: Calculate the middle index and check if it equals the target.
 Step 3: Determine which half of the array is sorted (left or right).
 Step 4: Check if the target lies within the sorted half's range.
 Step 5: Adjust the search boundaries based on where the target might be.
 Step 6: Continue the binary search until the target is found or search space is exhausted.
 Step 7: Return the index if found, otherwise return -1.

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