268. Missing Number; 41. First Missing Positive

268. Missing Number
class Solution(object):
    def missingNumber(self, nums):
        """
        :type nums: List[int]
        :rtype: int
        """
        n=len(nums)
        return sum(range(n+1))-sum(nums)

41. First Missing Positive
class Solution(object):
    def firstMissingPositive(self, nums):
        """
        :type nums: List[int]
        :rtype: int
        """
        first_positiove = 1
        flag=True
        if nums<>[]:
            if max(nums)>1:
                full_nums=range(1,max(nums)+1)
                for i in full_nums:
                    if i > 0 and i not in nums:
                        first_positiove = i
                        flag = False
                        break
                if flag:
                    first_positiove=max(nums)+1
            elif max(nums)==1:
                first_positiove =2
        return first_positiove