Find Minimum in Rotated Sorted Array
Prereq: Vanilla Binary Search and Finding the Boundary with Binary Search
A sorted array of unique integers was rotated at an unknown pivot. For example, [10, 20, 30, 40, 50] becomes [30, 40, 50, 10, 20]. Find the index of the minimum element in this array.
Input: [30, 40, 50, 10, 20]
Output: 3
Explanation: The smallest element is 10, and its index is 3.
Input: [3, 5, 7, 11, 13, 17, 19, 2]
Output: 7
Explanation: The smallest element is 2, and its index is 7.