1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
#include <iostream>
#include <vector>
#include <unordered_set>

typedef unsigned long long ull;
const int N = 3000;
const ull MOD = 1000000007; // yep, I need it
const bool tile = true;
const bool no_tile = false;
const std::hash<std::vector<bool>> hash;

int n, k;
std::vector<bool> plane;
std::unordered_set<std::vector<bool>> planes;

struct move
{
	int row, col;
};

inline int get_index(int row, int col) { return row * n + col; }

std::vector<move> get_possible_moves()
{
	std::vector<move> moves;
	for (int row = 0; row < n; ++row)
	{
		for (int col = 0; col < n; ++col)
		{
			if (plane[get_index(row, col)] == tile) continue;
			if(col - 1 >= 0 && plane[get_index(row, col - 1)] == tile ||
			   col + 1 < n && plane[get_index(row, col + 1)] == tile  ||
			   row - 1 >= 0 && plane[get_index(row - 1, col)] == tile  ||
			   row + 1 < n && plane[get_index(row + 1, col)] == tile)
			{
				moves.push_back({ row, col });
			}
		}
	}

	return moves;
}

void solve(int player)
{
	std::vector<move> moves = get_possible_moves();

	for(auto&& move : moves)
	{
		// do this move
		plane[get_index(move.row, move.col)] = tile;
		if(player + 1 == k)
		{
			// last player
			planes.insert(plane);
		}
		else
		{
			solve(player + 1);
		}
		plane[get_index(move.row, move.col)] = no_tile;
	}
}

int main()
{
	std::ios_base::sync_with_stdio(false);
	std::cin >> n >> k;
	plane.resize(n * n);

	char tmp;
	for(int row = 0; row < n; ++row)
	{
		for(int col = 0;  col < n; ++col)
		{
			std::cin >> tmp;
			plane[get_index(row, col)] = tmp == '#' ? tile : no_tile;
		}
	}

	solve(0);
	std::cout << planes.size();
	return 0;
}