'''

class Solution {

public:

vector<int> findDuplicates(vector<int>& nums) {

int len = nums.size();

vector<int>res;

for (int i = 0; i < len; i++) {

int m = abs(nums[i]) - 1;

nums[m] = - nums[m];

if (nums[m] > 0) {

res.push_back(m+1);

}

}

return res;

}

};

''''