import java.io.*;

/**
 * This class is used to solve a generalized version of the
 * Eight Queens Problem.
 */
public class QueensProblem
{
    public static final int MAX_DIMEN = 12;
    public static final int MIN_DIMEN = 2;
    public static final int DEFAULT_DIMEN = 8;
    private int dimen;
    private boolean[][] board;
    //---------------------------------------------------------------
    public QueensProblem(int inDimen)
    {
        if ((inDimen < MIN_DIMEN) || (inDimen > MAX_DIMEN))
        {
            dimen = DEFAULT_DIMEN;
        } // if
        else
        {
            dimen = inDimen;
        } // else

        board = new boolean[dimen][dimen];
    } // constructor QueensProblem(int)
    //---------------------------------------------------------------
    public void addQueen(int row, int col)
    {
        if ((row < 0) || (row >= dimen) || (col < 0) || (col >= dimen))
        {
            System.out.println("Bad queen position: (" + row + "," + col + ")");
        } // if
        else if (board[row][col])
        {
            System.out.println("Valid board position, but already occupied");
        } // else if
        else
        {
            board[row][col] = true;
        } // else
    } // addQueen(int,int)
    //---------------------------------------------------------------
    public void removeQueen(int row, int col)
    {
        if ((row < 0) || (row >= dimen) || (col < 0) || (col >= dimen))
        {
            System.out.println("Bad queen position: (" + row + "," + col + ")");
        } // if
        else if (!board[row][col])
        {
            System.out.println("Valid board position, but no queen to remove");
        } // else if
        else
        {
            board[row][col] = false;
        } // else
    } // removeQueen(int,int)
    //---------------------------------------------------------------
    public void printBoard()
    {
        int row, col;
        
        //--- Print a bunch of blank lines to move old board off screen ---
        for (int i = 0; i < 10; i++)
        {
            System.out.println("\n");
        } // for i

        // FILL IN HERE

    } // printBoard()
    //---------------------------------------------------------------
    /**
     * Prints "YES, two or more queens can attack each other." if any two
     * queens are lined up horizontally, vertically, or diagonally.
     * Prints "NO, there are no attacks." otherwise.
     */
    public void checkForAttacks()
    {
        // FILL IN HERE
    } // checkForAttacks()
    //---------------------------------------------------------------
} // class QueensProblem