public static IList <IList <string> > SolveNQueens(int n)
{
var output = new List <IList <string> >();
var q = new QueenBoard(n);
SolveNQueenHelper(q, 0, output);
return(output);
}
public static void SolveNQueenHelper(QueenBoard board, int row, IList <IList <string> > solutions)
{
if (row == board.Size)
{
solutions.Add(board.ToStringList());
return;
}
for (var col = 0; col < board.Size; col++)
{
var successfulPlacement = board.TryPlaceQueen(row, col);
if (successfulPlacement)
{
SolveNQueenHelper(board, row + 1, solutions);
board.RemoveQueen(row, col);
}
}
}