游戏扫雷器中二维数组递归的 StackOverflowError

Question

There is a function that explores cells around x and y by the rule :

If the cell is empty and has no mines around, all the cells around it, including the marked ones, can be explored

I'm used recursion to solve it, but catch StackOverflowError. Base case implemented by isEmptyAndNoMinesAround(int x, int y). Mines are marked as 'X'.

 public void exploreCell(int x, int y, String type) {

    if (!isEmptyAndNoMinesAround(x, y)) { //If the cell is empty and has no mines around, all the cells around it, including the marked ones, can be explored
        return;
    }

    userfield[x][y].setType(minefield[x][y].getType()); //explore cell on field

    //recur neighbors explore
    for (int xoff = -1; xoff <= 1; xoff++) {
        for (int yoff = -1; yoff <= 1; yoff++) {
            
            int i = x + xoff;
            int j = y + yoff;
            if (i > -1 && x < FIELD_SIZE && j > -1 && y < FIELD_SIZE) { //bound check

                exploreCell(i, j, type);

            }
        }
    }
}


    private boolean isEmptyAndNoMinesAround(int x, int y) {
    return minefield[x][y].getType() != 'X' && countMinesAround(x, y) == 0;
}

Answer 1

if you have two cells next to each other that fulfill the condition, you just hop endlessly between the two. You have to make sure you don't revisit the same squares.