void deleteDuplicates(node*& head) {
	std::unordered_set<int> seen;
	node* prev = nullptr;
	node* curr = head;
	while (curr != nullptr) {
		if (seen.find(curr->value) != seen.end()) {
			prev->next = curr->next;
			delete(curr);
		}
		else {
			seen.insert(curr->value);
			prev = curr;
		}
		curr = prev->next;
	}

}