Binary Search

def search(nums, target):
    left, right = 0, len(nums) - 1  # line 1
    while left <= right:             # line 2
        mid = (left + right) // 2    # line 3
        if nums[mid] == target:      # line 4
            return mid               # line 5
        elif nums[mid] < target:     # line 6
            left = mid + 1           # line 7
        else:                        # line 8
            right = mid - 1          # line 9
    return -1                        # line 10