Language: C++

#include <iostream>
#include <vector>
std::vector<std::pair<int, int>> next_list(const int &x, const int &y) {
	return { std::make_pair(x + 1, y), std::make_pair(x - 1, y), std::make_pair(x, y + 1), std::make_pair(x, y - 1) };
}
template<typename T>
class Queue {
public:
	Queue(const int &n) :vector(n), f(0), b(0) {};
	T front() const {
		return vector.at(f);
	}
	T back() const {
		return vector.at(b);
	}
	void pop() {
		f = (f + 1) % vector.size();
	}
	void push(T f) {
		vector.at(b) = f;
		b = (b + 1) % vector.size();
	}
	void clear() {
		f = 0;
		b = 0;
	}
private:
	std::vector<T> vector;
	int f, b;
};
struct Route {
	Route(const int &ax = 0, const int &ay = 0, const int &an = 0, const int &atime = 0) :x(ax), y(ay), n(an), time(atime) {};
	int x, y, n, time;
	bool operator<(const Route &other) const {
		return time < other.time;
	}
};
int wfs(const std::vector<std::vector<int>> &vector, std::vector<std::vector<int>> &memo, Queue<Route> &queue, const Route &start, const int &goal) {
	queue.clear();
	queue.push(start);
	while (vector.at(queue.front().y).at(queue.front().x) != start.n + 1) {
		for (const auto &coord : next_list(queue.front().x, queue.front().y)) {
			if (vector.at(coord.second).at(coord.first) >= 0 && memo.at(coord.second).at(coord.first) != start.n) {
				memo.at(coord.second).at(coord.first) = start.n;
				queue.push(Route(coord.first, coord.second, 0, queue.front().time + 1));
			}
		}
		queue.pop();
	}
	if (start.n + 1 == goal) {
		return queue.front().time;
	}
	else {
		return wfs(vector, memo, queue, Route(queue.front().x, queue.front().y, start.n + 1, queue.front().time), goal);
	}
}
int main() {
	int h, w, n;
	std::cin >> h >> w >> n;
	std::vector<std::vector<int>> vector(h + 2, std::vector<int>(w + 2, -1));
	Route start(0, 0, 0, 0);
	char *arg = new char[w + 2];
	for (auto i = 1; i <= h; ++i) {
		std::cin >> arg;
		for (auto j = 1; j <= w; ++j) {
			switch (arg[j - 1]) {
			case '.':
				vector.at(i).at(j) = 0;
				break;
			case 'X':
				vector.at(i).at(j) = -1;
				break;
			case 'S':
				vector.at(i).at(j) = 0;
				start = Route(j, i, 0, 0);
				break;
			default:
				vector.at(i).at(j) = arg[j - 1] - '0';
			}
		}
	}
	delete[] arg;
	arg = nullptr;
	std::cout << wfs(vector, std::vector<std::vector<int>>(h + 2, std::vector<int>(w + 2, -1)), Queue<Route>(h * w * 4), start, n);
	return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:84:39: error: cannot bind non-const lvalue reference of type 'std::vector<std::vector<int> >&' to an rvalue of type 'std::vector<std::vector<int> >'
   84 |         std::cout << wfs(vector, std::vector<std::vector<int>>(h + 2, std::vector<int>(w + 2, -1)), Queue<Route>(h * w * 4), start, n);
      |                                       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
a.cc:38:85: note:   initializing argument 2 of 'int wfs(const std::vector<std::vector<int> >&, std::vector<std::vector<int> >&, Queue<Route>&, const Route&, const int&)'
   38 | int wfs(const std::vector<std::vector<int>> &vector, std::vector<std::vector<int>> &memo, Queue<Route> &queue, const Route &start, const int &goal) {
      |                                                      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~