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?

class Solution {
public:
    int missingNumber(vector<int>& nums) {
    int res=0,i,n;
    n = nums.size();
    
    for(i=0;i<n;i++)
    {
        res ^= nums[i];
        res ^=(i+1);
        
    }
    return res;
    }
};