Problem
Given an array nums containing n distinct numbers in the range [0, n], return the only number in the range that is missing from the array.
Algorithm
Sum all the numbers as x x x and use n ( n + 1 ) 2 − x \frac{n(n+1)}{2} - x 2n(n+1)−x.
Code
class Solution:def missingNumber(self, nums: List[int]) -> int:sum_, n_ = 0, len(nums)for num in nums:sum_ += numreturn n_ * (n_ + 1) // 2 - sum_
))
)
