list<int> li;
for (int i = 0; i < 100; i++){
li.push_back(i);
}
for (int i = 0; i < 100; i++){
li.push_back(i);
}
unordered_set<int> uset(li.begin(), li.end()); //用list去初始化set
cout << uset.size() << endl;
for (auto i : uset){
cout << i << ",";
}