[LeetCode] Remove All Adjacent Duplicates In String

string removeDuplicates(string str) 
{
	stack<char> s;
	auto begin = str.begin(), end = str.end();

	while (begin != end)
	{
		auto ch = *begin;

		if (!s.empty() &&
			s.top() == ch)
			s.pop();

		else
			s.push(ch);

		begin++;
	}
	str.clear();

	while (!s.empty())
	{
		str.push_back(s.top());
		s.pop();
	}
	reverse(str.begin(), str.end());
	return str;
}