leetcode448 C++ 124ms 找到消失的数字

class Solution {
public:
    vector<int> findDisappearedNumbers(vector<int>& nums) {
        vector<int> res;
        int m;
        for(int i=0;i<nums.size();i++){
            m = abs(nums[i]) - 1;
            if(nums[m] > 0){
                nums[m] *= -1;
            }
        }
        for(int i=0;i<nums.size();i++){
            if(nums[i] > 0){
                res.push_back(i+1);
            }
        }
        return res;

    }
};