Missing Number

Problem: Missing Number

We just calculate the sum of the numbers in the list and sum of 0 to n and the difference will be our answer.

Code in Python:

class Solution(object):
    def missingNumber(self, nums):
        """
        :type nums: List[int]
        :rtype: int
        """
        sum1, sum2 = 0, 0
        for i in xrange(len(nums)):
            sum1, sum2 = sum1+nums[i], sum2+(i+1)
        return sum2-sum1