Given a sorted (in ascending order) integer array nums of n elements and a target value, write a function to search target in nums. If target exists, then return its index, otherwise return -1.

Example 1:

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

Output: 4

Explanation: 9 exists in nums and its index is 4

Example 2:

Input: nums = [-1,0,3,5,9,12], target = 2

Output: -1

Explanation: 2 does not exist in nums so return -1

Note:

1. You may assume that all elements in nums are unique.
2. n will be in the range [1, 10000].
3. The value of each element in nums will be in the range [-9999, 9999].

class Solution(object):

    def search(self, nums, target):

        """

        :type nums: List[int]

        :type target: int

        :rtype: int

        """

        n=len(nums)

        low=0

        high=n-1

        mid=(low+high)//2

        while low!=mid:

            if nums[mid]==target:

                return mid

            elif nums[mid]>target:

                high=mid

                mid=(high+low)//2

            elif nums[mid]<target:

                low=mid

                mid=(high+low)//2

        if nums[mid]==target:

            return mid

        elif nums[high]==target:

            return high

        else:

            return -1