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: n = len(nums) expectSum = int(n * (n+1) / 2) totalSum = 0 for i in nums: totalSum += i return expectSum - totalSum