Basic rotated search
Input
nums = [4,5,6,7,0,1,2], target = 0
Output
4
0 appears at index 4 in the rotated array.
Full lesson preview
Search in a rotated sorted array
Find the index of a target in a rotated sorted array using O(log n) time.
Python practice14 minSearching & SortingIntermediateLast updated March 25, 2026
Problem statement
You are given an array that was originally sorted in ascending order and then rotated at an unknown pivot. Implement a function that returns the index of a given target value in the array. If the target is not present, return -1. The array contains unique integers.
Task
Use a modified binary search to locate a target in a rotated sorted array without scanning linearly.
Examples
Input format
Two arguments: nums (list of unique integers), target (integer).
Output format
An integer index of target in nums, or -1 if not found.
Constraints
Time complexity: O(log n). Space complexity: O(1). Array length n >= 0. All elements are unique.
Samples
Sample 1
Input
nums = [6,7,1,2,3,4,5], target = 3
Output
4
3 is at index 4.