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Find Minimum in Rotated Sorted Array

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01 · Problem

Suppose an array of length n sorted in ascending order is rotated between 1 and n times. For example, the array nums = [0,1,2,4,5,6,7] might become:

  • [4,5,6,7,0,1,2] if it was rotated 4 times.
  • [0,1,2,4,5,6,7] if it was rotated 7 times.

Notice that rotating an array [a[0], a[1], a[2], ..., a[n-1]] 1 time results in the array [a[n-1], a[0], a[1], a[2], ..., a[n-2]].

Given the sorted rotated array nums of unique elements, return the minimum element of this array.

You must write an algorithm that runs in O(log n) time.

02 · Examples

Example 01
Input
nums = [3,4,5,1,2]
Output
1

The original array was [1,2,3,4,5] rotated 3 times.

Example 02
Input
nums = [4,5,6,7,0,1,2]
Output
0

The original array was [0,1,2,4,5,6,7] and it was rotated 4 times.

Example 03
Input
nums = [11,13,15,17]
Output
11

The original array was [11,13,15,17] and it was rotated 4 times (full rotation).

03 · Constraints

  • 01n == nums.length
  • 021 <= n <= 5000
  • 03-5000 <= nums[i] <= 5000
  • 04All the integers of nums are unique.
  • 05nums is sorted and rotated between 1 and n times.

04 · Optimal complexity

Time
O(log n)
Space
O(1)
05 · Two ways to work on it

Practice it alone or rehearse it as an interview.

Practice Mode gives you an editor and test runs, nothing else. AI Interview Mode puts a voice interviewer on the other side, adds a clock, and ends with a scored summary of the round.