Peaceful chess queen armies: Difference between revisions
→{{header|D}}
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* [https://oeis.org/A250000 A250000] OEIS
<br><br>
=={{header|C#|C sharp}}==
{{trans|D}}
<lang csharp>using System;
using System.Collections.Generic;
namespace PeacefulChessQueenArmies {
using Position = Tuple<int, int>;
enum Piece {
Empty,
Black,
White
}
class Program {
static bool IsAttacking(Position queen, Position pos) {
return queen.Item1 == pos.Item1
|| queen.Item2 == pos.Item2
|| Math.Abs(queen.Item1 - pos.Item1) == Math.Abs(queen.Item2 - pos.Item2);
}
static bool Place(int m, int n, List<Position> pBlackQueens, List<Position> pWhiteQueens) {
if (m == 0) {
return true;
}
bool placingBlack = true;
for (int i = 0; i < n; i++) {
for (int j = 0; j < n; j++) {
var pos = new Position(i, j);
foreach (var queen in pBlackQueens) {
if (queen.Equals(pos) || !placingBlack && IsAttacking(queen, pos)) {
goto inner;
}
}
foreach (var queen in pWhiteQueens) {
if (queen.Equals(pos) || placingBlack && IsAttacking(queen, pos)) {
goto inner;
}
}
if (placingBlack) {
pBlackQueens.Add(pos);
placingBlack = false;
} else {
pWhiteQueens.Add(pos);
if (Place(m - 1, n, pBlackQueens, pWhiteQueens)) {
return true;
}
pBlackQueens.RemoveAt(pBlackQueens.Count - 1);
pWhiteQueens.RemoveAt(pWhiteQueens.Count - 1);
placingBlack = true;
}
inner: { }
}
}
if (!placingBlack) {
pBlackQueens.RemoveAt(pBlackQueens.Count - 1);
}
return false;
}
static void PrintBoard(int n, List<Position> blackQueens, List<Position> whiteQueens) {
var board = new Piece[n * n];
foreach (var queen in blackQueens) {
board[queen.Item1 * n + queen.Item2] = Piece.Black;
}
foreach (var queen in whiteQueens) {
board[queen.Item1 * n + queen.Item2] = Piece.White;
}
for (int i = 0; i < board.Length; i++) {
if (i != 0 && i % n == 0) {
Console.WriteLine();
}
switch (board[i]) {
case Piece.Black:
Console.Write("B ");
break;
case Piece.White:
Console.Write("W ");
break;
case Piece.Empty:
int j = i / n;
int k = i - j * n;
if (j % 2 == k % 2) {
Console.Write(" ");
} else {
Console.Write("# ");
}
break;
}
}
Console.WriteLine("\n");
}
static void Main() {
var nms = new int[,] {
{2, 1}, {3, 1}, {3, 2}, {4, 1}, {4, 2}, {4, 3},
{5, 1}, {5, 2}, {5, 3}, {5, 4}, {5, 5},
{6, 1}, {6, 2}, {6, 3}, {6, 4}, {6, 5}, {6, 6},
{7, 1}, {7, 2}, {7, 3}, {7, 4}, {7, 5}, {7, 6}, {7, 7},
};
for (int i = 0; i < nms.GetLength(0); i++) {
Console.WriteLine("{0} black and {0} white queens on a {1} x {1} board:", nms[i, 1], nms[i, 0]);
List<Position> blackQueens = new List<Position>();
List<Position> whiteQueens = new List<Position>();
if (Place(nms[i, 1], nms[i, 0], blackQueens, whiteQueens)) {
PrintBoard(nms[i, 0], blackQueens, whiteQueens);
} else {
Console.WriteLine("No solution exists.\n");
}
}
}
}
}</lang>
{{out}}
<pre>1 black and 1 white queens on a 2 x 2 board:
No solution exists.
1 black and 1 white queens on a 3 x 3 board:
B #
# W
#
2 black and 2 white queens on a 3 x 3 board:
No solution exists.
1 black and 1 white queens on a 4 x 4 board:
B # #
# W
# #
# #
2 black and 2 white queens on a 4 x 4 board:
B # #
# W
B # #
# W
3 black and 3 white queens on a 4 x 4 board:
No solution exists.
1 black and 1 white queens on a 5 x 5 board:
B # #
# W #
# #
# # #
# #
2 black and 2 white queens on a 5 x 5 board:
B # # B
# W #
W #
# # #
# #
3 black and 3 white queens on a 5 x 5 board:
B # # B
# W #
W #
# # B #
W #
4 black and 4 white queens on a 5 x 5 board:
B B
# # B
W # W #
# # B
W # W #
5 black and 5 white queens on a 5 x 5 board:
No solution exists.
1 black and 1 white queens on a 6 x 6 board:
B # # #
# W #
# # #
# # #
# # #
# # #
2 black and 2 white queens on a 6 x 6 board:
B # # B #
# W #
W # #
# # #
# # #
# # #
3 black and 3 white queens on a 6 x 6 board:
B # # B B
# W #
W # #
# # #
# W # #
# # #
4 black and 4 white queens on a 6 x 6 board:
B # # B B
# W #
W # #
# # # B
# W W #
# # #
5 black and 5 white queens on a 6 x 6 board:
B # B #
# # B # B
W # # #
W W #
# # B
W W #
6 black and 6 white queens on a 6 x 6 board:
No solution exists.
1 black and 1 white queens on a 7 x 7 board:
B # # #
# W # #
# # #
# # # #
# # #
# # # #
# # #
2 black and 2 white queens on a 7 x 7 board:
B # # B #
# W # W
# # #
# # # #
# # #
# # # #
# # #
3 black and 3 white queens on a 7 x 7 board:
B # # B #
# W # W
B # # #
# W # #
# # #
# # # #
# # #
4 black and 4 white queens on a 7 x 7 board:
B # # B #
# W # W
B # # B #
# W # W
# # #
# # # #
# # #
5 black and 5 white queens on a 7 x 7 board:
B # # B #
# W # W
B # # B #
# W # W
B # # #
# W # #
# # #
6 black and 6 white queens on a 7 x 7 board:
B # # B #
# W # W
B # # B #
# W # W
B # # B #
# W # W
# # #
7 black and 7 white queens on a 7 x 7 board:
B # B
# B # B #
B # B
# # B #
W # W # # W
# # W # #
W # W W #</pre>
=={{header|D}}==
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