Missing Number Python

Given an array containing n distinct numbers taken from 0, 1, 2, ..., n, find the one that is missing from the array.

Example 1:

Input: [3,0,1]
Output: 2

Example 2:

Input: [9,6,4,2,3,5,7,0,1]
Output: 8

Note:
Your algorithm should run in linear runtime complexity. Could you implement it using only constant extra space complexity?

class Solution:
    def missingNumber(self, nums: List[int]) -> int:
        nums.sort()
        if nums[0] != 0:
            return 0        elif nums[-1] != len(nums):
            return len(nums)

        for i in range(0, len(nums)):
            if i != nums[i]:
                return i


Time Complexity : O(nlogn) // sorting
Space Complexity : O(1)