# 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:
#
# You may assume that all elements in nums are unique.
# n will be in the range [1, 10000].
# 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
        """
        l, r = 0, len(nums) - 1  # knowledge r's value
        while l <= r:  # knowledge should be <= instead of <
            mid = l + (r - l) / 2
            if nums[mid] == target:
                return mid
            elif nums[mid] > target:
                r = mid - 1
            else:
                l = mid + 1

        return -1


if __name__ == '__main__':
    print Solution().search([2, 5], 5)
    print Solution().search([5], 5)
    print Solution().search([-1, 0, 3, 5, 9, 12], 2)
    print Solution().search([-1, 0, 3, 5, 9, 12], 9)
    print Solution().search([-1, 0, 3, 5, 9, 12], -1)
