LeetCode 0268 - Missing Number

Missing Number

Desicription

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

Example 1:

Input: [3,0,1]
Output: 2

Example 2:

Input: [9,6,4,2,3,5,7,0,1]
Output: 8

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

Solution

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