LeetCode 之 Missing Number

Given an array containing n distinct numbers taken from 0, 1, 2, ..., n, find the one that is missing from the array.

For example,
Given nums = [0, 1, 3] return 2.

Note:

Your algorithm should run in linear runtime complexity. Could you implement it using only constant extra space complexity?

这个题挺简单的，代码如下：

int missingNumber(vector<int>& nums) {
        int sum=0;
        for (auto x : nums){
            sum+=x;
        }
        return nums.size()*(nums.size()+1)/2-sum;
    }