Given a sorted array of integers, write a function to search for a target value. If the target exists in the array, return its index. If it does not, return -1. Your algorithm should have O(log n) complexity. ### Function Signature ```python def binary_search(nums: List[int], target: int) -> int: ``` ### Constraints - `1 <= nums.length <= 10^4` - `-10^4 <= nums[i], target <= 10^4` - All integers in `nums` are unique. ### Examples 1. Input: `binary_search([1, 2, 3, 4, 5], 3)` Output: `2` 2. Input: `binary_search([1, 2, 3, 4, 5], 6)` Output: `-1`