Binary Search
You are given an array of distinct integers nums, sorted in ascending order, and an integer target.

Implement a function to search for target within nums. If it exists, then return its index, otherwise, return -1.

Your solution must run in O(logn) time.

Example 1:

Input: nums = [-1,0,2,4,6,8], target = 4

Output: 3
Example 2:

Input: nums = [-1,0,2,4,6,8], target = 3

Output: -1
Constraints:

1 <= nums.length <= 10000.
-10000 < nums[i], target < 10000