153. Find Minimum in Rotated Sorted Array

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:

Example 1:

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

Example 2:

• Input: nums = [4,5,6,7,0,1,2]
• Output: 0
• Explanation: The original array was [0,1,2,4,5,6,7] and it was rotated 4 times.

Example 3:

• Input: nums = [11,13,15,17]
• Output: 11
• Explanation: The original array was [11,13,15,17] and it was rotated 4 times.

Constraints:

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

Approach

Solution

class Solution:
    def findMin(self, nums: List[int]) -> int:
        l, r = 0, len(nums) - 1
        lowest_index = -1

        while l <= r:
            m = (l + r) // 2
            if nums[m] <= nums[-1]:
                lowest_index = m
                r = m - 1
            else:
                l = m + 1

        return nums[lowest_index]

Explanation