153. Find minimum in rotated sorted array

Find Minimum in Rotated Sorted Array - LeetCode

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.

Example 1: Input: nums = [3,4,5,1,2] Output: 1 Explanation: The original array was [1,2,3,4,5] rotated 3 times.


  • code
class Solution:
    def findMin(self, nums: List[int]) -> int:
        left, right = 0, len(nums)-1
        while left < right:
            mid = left + (right - left) // 2
            if nums[mid] > nums[left]:
                if nums[right] > nums[mid]:
                    right = mid - 1
                else:
                    left = mid + 1
            elif nums[mid] < nums[right]:
                right = mid
            else: # mid <= left, mid >= right
                left = mid + 1

        return nums[left]
        

  • code
class Solution:
    def findMin(self, nums: List[int]) -> int:
        left, right = 0, len(nums)-1
        while left < right:
            mid = left + (right - left) // 2
            if nums[mid] > nums[right]:
                left = mid + 1
            else:  # mid <= right
                right = mid

        return nums[left]