如何检查 2D 字符数组中某行的特定元素，然后计算该行中该元素的数量？ (Java)

Question

这是一个 N Queens 问题，其中给出了棋盘，您必须使用方法来检查行、列和对角线的位置。我检查行的方法在这里：如果你把皇后区作为一个整体来计算，它是有效的，但我只想逐行检查，重置计数和行数。

private boolean oneQueenPerRow() //ensures that there is only 1 queen in each row
{
    int count = 0;
    int rowcount = 0;
    for (int i = 0; i < board.length; i++)
    {
        //count  = 0;
        for (int j = 0; j < board.length; j++)
        {
            //rowcount = 0;
            while (rowcount <= size-1)
            {
                if (board[i][j] == QUEEN)
                {
                    count++;
                    rowcount++;  
                }
                if (board[i][j] == BLANK)
                {
                    rowcount++;
                }
            }
            if (count != 1) // if size replaces 1 then it works, but counts Q's as a whole
            {
                return false;
            }             
        } 
    }
    return true;
}

想法是所有方法 return true 或 false 然后由最终布尔方法调用。如果一切都是真的，那么该板就是一个有效的解决方案。如果一个是错误的，则该板不是有效的解决方案。这是我得到的文本文件示例：

4 BQBB 烧烤 QBBB 烧烤

（它们应该堆叠..）

我对数组和 for 循环的了解不够，无法判断这是遍历整个文件还是一次只遍历一行，尽管相信我，我已经用尽了所有资源。

几天来我一直在研究这个问题，但我无法弄清楚，而且由于这个病毒，我与教授的联系也很不稳定！我迫切需要帮助！

private boolean noDiagonalAttacks() //makes sure that Queens cannot attack diagonally
    {
        for (int i = 0; i < board.length; i++)
        {
            int count = 0;
            for (int j = 0; j < board.length; j++)
            {
                if (board[i][j] == QUEEN)
                {
                    if(this.toRight() == false || this.toLeft() == false)
                    {
                        return false;
                    }
                    count++;
                }
            }
        }
        return true;
    }

    private boolean toRight()
    {
        for (int i = 0; i < board.length; i++)
        {
            for (int j = 0; j < board.length; j++)
            {
                while (board[i][j] != board[i][size-1] || board[i][j] != board[size-1][j]) //add a count to this?
                {
                    if (board[i][j] == QUEEN)
                    {
                        return false;
                    }
                }
            }    
        } 
        return true;       
    }

    private boolean toLeft()
    {
        for (int i = 0; i < board.length; i++)
        {
            for (int j = 0; j < board.length; j++)
            {
                while (board[i][j] != board[i][0] || board[i][j] != board[size-1][j])
                {
                    if (board[i][j] == QUEEN)
                    {
                        return false;
                    }
                }
            }
        }    
        return true;
    }

Answer 1

之前试过一次，效果不错，希望对你有帮助。

private boolean oneQueenPerRow() {
    int foundQueens;
    for (int i = 0; i < board.length; i++) {
        foundQueens = 0;//each loop is a checked row
        for (int j = 0; j < board.length; j++) {
            if (board[i][j] == QUEEN)
                foundQueens++;
        }
        if (foundQueens > 1) return false;
    }
    return true;
}

private boolean oneQueenPerDiagonal() {
    int inLeftRight = 0;
    int inRightLeft = 0;
    for (int i = 0; i < board.length; i++) {
        if (board[i][i] == QUEEN)
            inLeftRight++;
        if (board[i][board.length-i-1] == QUEEN)
            inRightLeft++;
    }
    return inLeftRight < 1 && inRightLeft < 1;
}

如何检查 2D 字符数组中某行的特定元素，然后计算该行中该元素的数量？ (Java)

How do you check a row in a 2D char array for a specific element and then count how many of that element are in the row? (Java)

java

arrays

2d

rows

n-queens