class Solution {
public:
    vector<int> findDisappearedNumbers(vector<int>& nums) {
        vector<int> result, count(nums.size()+1);
        count[0]=1;
        for(int i=0; i<nums.size(); ++i)
        {
            ++count[nums[i]];
        }
        for(int i=1; i<count.size(); ++i)
        {
            if(count[i]==0) result.push_back(i);
        }
        return result;
    }
};```