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