Java 生成数独网格时出现意外输出

我编写了以下类来生成数独网格。我无法理解该计划的一些结果。有人能解释一下吗

public class SudokuUtility {

    static final int max = 8;
    static final int min = 0;
    static final int digitMax = 9;
    static final int digitMin = 0;

    static final int easyMin = 36;
    static final int easyMax = 49;

    static final int mediumMin = 32;
    static final int mediumMax = 40;

    static final int hardMin = 22;
    static final int hardMax = 30;


    public static int[][] makeAGrid(String option) {

        int[][] grid = new int[9][9];

        option = "hard";

        Random random = new Random();

        int row = 0;
        int col = 0;

        int randomNumber = 0;
        int noOfCellsToBeGenerated = 0;

        if ("easy".equals(option)) {
            noOfCellsToBeGenerated = random.nextInt((easyMax - easyMin) + 1) + easyMin;
        } else if ("medium".equals(option)) {
            noOfCellsToBeGenerated = random.nextInt((mediumMax - mediumMin) + 1) + mediumMin;
        } else {
            noOfCellsToBeGenerated = random.nextInt((hardMax - hardMin) + 1) + hardMin;
        }

        for (int i = 1; i <= noOfCellsToBeGenerated; i++) {
            row = random.nextInt((max - min) + 1) + min;
            col = random.nextInt((max - min) + 1) + min;
            randomNumber = random.nextInt((digitMax - digitMin) + 1) + digitMin;

            if (noConflict(grid, row, col, randomNumber)) {
                grid[row][col] = randomNumber;
            } else {
                i = i - 1; // Nullify this iteration
            }
        }

        int zeroCount = 0;

        for (int i = 0; i < 9; i++) {
            for (int j = 0; j < 9; j++) {
                if (grid[i][j] == 0) {
                    zeroCount++;
                }
                System.out.print(grid[i][j] + "  ");
            }
            System.out.println();
        }
        System.out.println("No of zeros in the " + option + " puzzle = " + zeroCount + " and noOfCellsGenerated = " + noOfCellsToBeGenerated);

        return grid;
    }

    public static boolean noConflict(int[][] array, int row, int col, int num) {

        for (int i = 0; i < 9; i++) {
            if (array[row][i] == num) {
                return false;
            }
            if (array[i][col] == num) {
                return false;
            }
        }

        int gridRow = row - (row % 3);
        int gridColumn = col - (col % 3);
        for (int p = gridRow; p < gridRow + 3; p++) {
            for (int q = gridColumn; q < gridColumn + 3; q++) {
                if (array[p][q] == num) {
                    return false;
                }
            }
        }
        return true;
    }
}

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应该有24个生成的数字。实际上有21个。我的逻辑错了吗？但我对逻辑很有把握。我的理解中缺少了什么？

我已经在运行您的代码时添加了一些日志记录，这个问题正是我在评论中的意思

如果两次命中同一单元格（行、列），但随机值不同，

noConflict

返回

true

，旧值将被覆盖

---

您应该检查

noConflict

方法中的单元格是否为空。

如果您两次点击同一单元格（行、列），该怎么办？我的意思是，如果它已经包含一个数字。@enlait我已经取消了那个迭代。所以它发生了4次，这就解释了区别。@helderdarocha我有一个语句I=I-1；它不是使冲突的位置无效吗？

0  6  0  0  0  1  0  7  0  
0  9  0  4  0  0  0  1  0  
0  8  0  0  3  0  0  0  0  
0  0  0  7  0  0  0  0  0  
9  0  0  8  0  0  0  0  0  
0  7  0  0  6  0  2  0  0  
7  5  0  0  0  0  0  0  9  
8  0  0  0  4  0  0  0  0  
0  1  0  0  7  0  0  6  0  

No of zeros in the hard puzzle = 59 and noOfCellsGenerated = 24