【python】二分查找算法

nums = [-1, 1,2,3]
target = 3

class Solution:
    #定义全局变量，记录右边一半时的偏移量
    global num_count
    num_count = 0
    def search(self, nums, target):
        global num_count

        if int(len(nums)) == 0:
            return -1
        elif target in nums:
            mid = int(len(nums) / 2)
            if nums[mid] == target:
                //最后返回时，需要加上右边的偏移量
                return mid+num_count
            elif nums[mid] > target:
                new_nums = nums[0:mid]
                return self.search(new_nums, target)
            elif nums[mid] < target:
                //左边不需要加，右边需要加上偏移量
                num_count += mid
                new_nums = nums[mid:int(len(nums))]
                return self.search(new_nums, target)
            else:
                return -1
        else:
            return -1

aa = Solution()
bb = aa.search(nums, target)
print(bb)