268. 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.
Solution: [Math]
class Solution {
public:
    int missingNumber(vector<int>& nums)
    {
        int n = nums.size();
        int sum = 0;
        for(int i=0; i<n; i++) {sum += nums[i];}
        
        return n*(n+1)/2-sum;
    }
};