LeetCode 268 – Python 3 (Week 06 – 08)

class Solution:
    def missingNumber(self, nums: List[int]) -> int:
        sum = len(nums) * （len(nums) + 1）/ 2
        for i in range(len(nums)):
            sum -= nums[i]
            
        return sum

class Solution:
    def missingNumber(self, nums: List[int]) -> int:
        miss = len(nums)
        
        for i in range(len(nums)):
            miss ^= i ^ nums[i]
            
        return miss