LC704. Binary Search

class Solution:
    def search(self, nums: List[int], target: int) -> int:
        l, r = 0, len(nums) - 1
 
        while l <= r:
            mid = l + (r - l) // 2
 
            if nums[mid] == target:
                return mid
            
            if target < nums[mid]:
                r = mid - 1
            else:
                l = mid + 1
        
        return -1

Complexity

Time: $O(logn)$
Space: $O(1)$