class Solution {
public:
vector<vector<int>> findDifference(vector<int>& nums1, vector<int>& nums2) {
unordered_set<int> set1,set2;
for(int num:nums1){
set1.insert(num);
}
for(int num:nums2){
set2.insert(num);
}
vector<vector<int>> res(2);
for(int num:set1){
if(!set2.count(num)){
res[0].push_back(num);
}
}
for(int num:set2){
if(!set1.count(num)){
res[1].push_back(num);
}
}
return res;
}
};