I tried to solve this problem using BFS on priority queue with a custom comparator ,but getting WA ,and I really wanna know if the main idea is wrong or there is something in the code code

struct Compare {
	bool operator()(pair<string, int> const& p1, pair<string, int> const& p2)
	{
		if (p1.first.length() == p2.first.length())
			return p1.first > p2.first;
		return p1.first.length() > p2.first.length();
	}
};