0, 1, 2, ..., n, find the one that is missing from the array.For example,
Given nums = [0, 1, 3] return 2.
class Solution(object): def missingNumber(self, nums): """ :type nums: List[int] :rtype: int """ n = len(nums) return (1+n)*n/2-sum(nums)
原文：http://www.cnblogs.com/jkmiao/p/4811456.html