Leetcode448. 找到所有数组中消失的数字

class Solution {
public:
    vector<int> findDisappearedNumbers(vector<int>& nums) {
        vector<int> res;
        int n=nums.size(),offset=n+1;
        for(auto &num:nums)
        {
            int x=(num)%offset;
            nums[x-1]+=offset;
        }
        for(int i=0;i<n;i++)
            if(nums[i]<=offset)   
                res.push_back(i+1);
        return res;
    }
};