704. 二分查找(search)

class Solution(object):
    def search(self, nums, target):
        """
        :type nums: List[int]
        :type target: int
        :rtype: int
        """
        begin = 0
        end = len(nums) - 1
        while(begin <= end):
            half = begin + (end - begin) // 2
            if target > nums[half]:
                begin = half + 1
            elif target < nums[half]:
                end = half - 1
            else:
                return half
        return -1