Binary Search

Given an array of integers nums which is sorted in ascending order, and an integer target, write a function to search target in nums. If target exists, then return its index. Otherwise, return -1.

You must write an algorithm with O(log n) runtime complexity.

Example 1

Input: nums = [-1,0,3,5,9,12], target = 9
Output: 4

Constraints

• 1 <= nums.length <= 10^4
• -10^4 < nums[i], target < 10^4
• All integers in nums are unique.