算法1

(二分法) $O(log(n))$

blablabla

时间复杂度分析：blablabla

python 代码

class Solution(object):
    def getMissingNumber(self, nums):
        """
        :type nums: List[int]
        :rtype: int
        """
        if not nums or nums[0]!=0:
            return 0
        l,r=0,len(nums)-1
        mid=0
        while l<r:
            mid=(l+r)//2
            if nums[mid]==mid:
                l=mid+1
            else:
                r=mid
        if nums[l]==l:
            return len(nums)
        else:
            return (nums[l-1]+1)