java - 递归溢洪溢出

Question

public void floodFill(int x, int y) {
    if (x >= 0 && x <= 9 && y >= 0 && y <= 9) {
        if (mines[x][y] == 0) {
            btn[x][y].setBackground(Color.GRAY);
            floodFill(x - 1, y);
            // floodFill(x + 1, y);
            floodFill(x, y - 1);
            // floodFill(x, y + 1);
        } else {
            return;
        }
    }
}

这是我正在制作的类似扫雷游戏的 floodFill 代码。但是，如您所见，有 2 个部分被注释掉了。一旦我取消注释并运行程序。

Exception in thread "AWT-EventQueue-0" java.lang.StackOverflowError
at sun.awt.NullComponentPeer.setBackground(Unknown Source)
at java.awt.Component.setBackground(Unknown Source)
at javax.swing.JComponent.setBackground(Unknown Source)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:95)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:99)
at Minesweeper.BoardBuild.floodFill(BoardBuild.java:98)

我不确定为什么会这样，也不知道如何解决。任何帮助表示赞赏。

编辑：

Fls'Zen 在聊天中给出的答案，以防万一其他人遇到这个问题

public void floodFill(int x, int y) {
    if (x >= 0 && x <= 9 && y >= 0 && y <= 9) {
        if (mines[x][y] == 0 && btn[x][y].getBackground() != Color.GRAY) {
            btn[x][y].setBackground(Color.GRAY);
            floodFill(x - 1, y);
            floodFill(x + 1, y);
            floodFill(x, y - 1);
            floodFill(x, y + 1);
        } else {
            return;
        }
    }
}

score 4 · Accepted Answer

当这些行未注释时，您调用 floodFillx - 1和x + 1。考虑当您调用 floodFill 时会发生什么x - 1。它还调用floodFill，x + 1它的x值是调用floodFill 的值。您有 floodFill 为相同的两个x值调用自己，原始x值和原始值x - 1。

如果您要使用递归，您应该选择一个“方向”（+ 或 -）并坚持下去。否则，您需要添加一些内容来跟踪已评估的坐标。

编辑： 当算法已经处理了单元格时，以下代码将避免递归。它通过检查当前坐标的背景颜色来实现这一点。如果背景已经是灰色的，那么它假定它已经处理了坐标并且不会再次处理它们。

if (mines[x][y] == 0 && btn[x][y].getBackground() != Color.GRAY) {
    btn[x][y].setBackground(Color.GRAY);
    floodFill(x - 1, y);
    floodFill(x + 1, y);
    floodFill(x, y - 1);
    floodFill(x, y + 1);
} else {
    return;
}

score 0 · Accepted Answer

0

看起来你没有记录你已经检查过的方块，所以它在整个棋盘上无限循环。

于 2012-12-29T00:34:09.227 回答

java - 递归溢洪溢出

2 回答 2

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