Ratsun reitit

input/code.cpp: In member function 'void board::set_next(std::vector<std::pair<int, int> >, int)':
input/code.cpp:11:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int i = 0; i < positions.size(); i++)
                   ~~^~~~~~~~~~~~~~~~~~
input/code.cpp: In constructor 'board::board(int)':
input/code.cpp:89:6: warning: 'board::dimension' will be initialized after [-Wreorder]
  int dimension;
      ^~~~~~~~~
input/code.cpp:88:19: warning:   'std::vector<int> board::elements' [-Wreorder]
  std::vector<int> elements;
                   ^~~~~~~~
input/code.cpp:42:2: warning:   when initialized here [-Wreorder]
  board(int dim)
  ^~~~~
input/code.cpp: In member function 'void board::horse_board(int, int)':
input/code.cpp:81:7: warning: unused variable 'n_moves' [-Wunused-variable]
   int n_moves = 0;
       ^~~~~~~

#include <iostream>
#include <vector>


class board
{
private:
	void set_next(std::vector<std::pair<int, int>> positions, int val)
	{
		std::vector<std::pair<int, int>> new_positions;
		for (int i = 0; i < positions.size(); i++)
		{
			if (set_pos(positions[i].first, positions[i].second, val))
			{
				for (auto p : get_positions(positions[i].first, positions[i].second))
				{
					new_positions.emplace_back(p);
				}
			}
		}
		if (!board_full())
			set_next(new_positions, ++val);
	}
	std::vector<std::pair<int, int>> get_positions(int x, int y)
	{
		return { {x - 1, y - 2},{x + 1, y - 2},{x + 2, y - 1},{x + 2, y + 1},{x + 1, y + 2},{x - 1,y + 2},{x - 2, y + 1},{x - 2,y - 1} };
	}
	bool on_board(int x, int y)
	{
		return (x < dimension&& x >= 0 && y < dimension&& y >= 0);
	}
	bool board_full()
	{
		for (int i = 0; i < dimension * dimension; i++)
		{
			if (elements[i] == -1)
				return 0;
		}
		return 1;
	}
public:
	board(int dim)
		:
		dimension(dim),
		elements(dim*dim, -1)
	{}
	void print()
	{
		for (int y = 0; y < dimension; y++)
		{
			for (int x = 0; x < dimension; x++)
			{
				std::cout << elements[y * dimension + x] << " ";
			}
			std::cout << '\n';
		}
	}
	bool set_pos(int x, int y, int val)
	{
		if (on_board(x, y) && elements[y * dimension + x] == -1)
		{
			elements[y * dimension + x] = val;
			return 1;
		}
		else
			return 0;
	}
	int get_pos(int x, int y)
	{
		if (on_board(x, y))
			return elements[y * dimension + x];
		else
			return -1;
	}
	int get_dim()
	{
		return dimension;
	}
	void horse_board(int start_x, int start_y)
	{
		int n_moves = 0;
		elements[start_y * dimension + start_x] = 0;

		set_next(get_positions(start_x, start_y), 1);
		
	}
private:
	std::vector<int> elements;
	int dimension;
};



int main()
{
	int dim;
	std::cin >> dim;
	board brd(dim);
	brd.horse_board(0, 0);
	brd.print();
	return 0;
}

Test 1

Group: 1, 2, 3

Verdict: ACCEPTED

Test 2

Group: 1, 2, 3

Verdict: ACCEPTED

Test 3

Group: 1, 2, 3

Verdict: ACCEPTED

Test 4

Group: 1, 2, 3

Verdict: ACCEPTED

Test 5

Group: 1, 2, 3

Verdict: ACCEPTED

Test 6

Group: 1, 2, 3

Verdict: ACCEPTED

Test 7

Group: 1, 2, 3

Verdict: ACCEPTED

Test 8

Group: 2, 3

Verdict: ACCEPTED

Test 9

Group: 2, 3

Verdict: ACCEPTED

Test 10

Group: 2, 3

Verdict: ACCEPTED

Test 11

Group: 3

Verdict: ACCEPTED

Test 12

Group: 3

Verdict: ACCEPTED

Test 13

Group: 3

Verdict: ACCEPTED