从您发布的代码中,我看不到任何问题可以解释您的问题。但是,您尚未发布可自行编译和执行的代码(称为最小工作或可验证示例,请参阅Wikipedia和StackOverflow's guide on creating one),也没有发布适用于您的应用程序的堆栈跟踪或输出。这使得你很难帮助你解决你的问题。如果你能为我提供更多,我愿意继续帮助你解决你的问题。
在此期间,我试图拼凑可以解决以下你的方法相同的问题的程序。它似乎工作,虽然我没有彻底的单元测试它。也许你可以将它与你所写的内容进行比较,并利用差异来发现问题。您至少需要Java 7才能编译并运行此代码。
如果这是作业作业,我建议在查看此列表之前向您的教授或TA查询。
public class Main {
public static void main(String[] args) {
Sudoku puzzle = new Sudoku();
// Uncomment these lines to have a uniquely solvable Sudoku puzzle. They are commented out to prove that this code can count multiple solutions.
// puzzle.set(1, 0, 2);
// puzzle.set(2, 0, 9);
// puzzle.set(4, 0, 5);
// puzzle.set(7, 0, 4);
// puzzle.set(8, 0, 1);
// puzzle.set(3, 1, 8);
// puzzle.set(6, 1, 3);
// puzzle.set(2, 2, 3);
puzzle.set(3, 2, 7);
puzzle.set(4, 2, 4);
puzzle.set(5, 2, 9);
puzzle.set(6, 2, 6);
puzzle.set(3, 3, 4);
puzzle.set(6, 3, 2);
puzzle.set(7, 3, 1);
puzzle.set(1, 4, 6);
puzzle.set(3, 4, 3);
puzzle.set(4, 4, 7);
puzzle.set(5, 4, 1);
puzzle.set(7, 4, 8);
puzzle.set(1, 5, 4);
puzzle.set(2, 5, 1);
puzzle.set(5, 5, 6);
puzzle.set(2, 6, 5);
puzzle.set(3, 6, 9);
puzzle.set(4, 6, 2);
puzzle.set(5, 6, 8);
puzzle.set(6, 6, 7);
puzzle.set(2, 7, 4);
puzzle.set(5, 7, 7);
puzzle.set(0, 8, 3);
puzzle.set(1, 8, 7);
puzzle.set(4, 8, 6);
puzzle.set(6, 8, 5);
puzzle.set(7, 8, 2);
SudokuSolver solver = new SudokuSolver(puzzle);
long start = System.nanoTime();
int totalSolutions = solver.compute();
long end = System.nanoTime();
System.out.println(totalSolutions);
System.out.format("%f ms", (end - start)/1e6);
}
private static class Sudoku {
private final int[][] cells;
Sudoku() {
cells = new int[9][9];
}
Sudoku(Sudoku original) {
cells = new int[9][9];
for (int column = 0; column < 9; ++column) {
for (int row = 0; row < 9; ++row) {
set(column, row, original.get(column, row));
}
}
}
int get(int column, int row) {
return cells[column][row];
}
void set(int column, int row, int value) {
cells[column][row] = value;
}
boolean isPlausible() {
return columnsArePlausible() && rowsArePlausible() && blocksArePlausible();
}
private boolean columnsArePlausible() {
boolean result = true;
for (int column = 0; result && column < 9; ++column) {
result = isColumnPlausible(column);
}
return result;
}
private boolean isColumnPlausible(int column) {
boolean result = true;
boolean[] seen = new boolean[10];
for (int row = 0; result && row < 9; ++row) {
int value = get(column, row);
if (value > 0 && seen[value]) {
result = false;
} else {
seen[value] = true;
}
}
return result;
}
private boolean rowsArePlausible() {
boolean result = true;
for (int row = 0; result && row < 9; ++row) {
result = isRowPlausible(row);
}
return result;
}
private boolean isRowPlausible(int row) {
boolean result = true;
boolean[] seen = new boolean[10];
for (int column = 0; result && column < 9; ++column) {
int value = get(column, row);
if (value > 0 && seen[value]) {
result = false;
} else {
seen[value] = true;
}
}
return result;
}
private boolean blocksArePlausible() {
boolean result = true;
for (int column = 0; result && column < 9; column += 3) {
for (int row = 0; result && row < 9; row += 3) {
result = isBlockPlausible(column, row);
}
}
return result;
}
private boolean isBlockPlausible(int column, int row) {
boolean result = true;
boolean[] seen = new boolean[10];
for (int x = 0; result && x < 3; ++x) {
for (int y = 0; result && y < 3; ++y) {
int value = get(column + x, row + y);
if (value > 0 && seen[value]) {
result = false;
} else {
seen[value] = true;
}
}
}
return result;
}
}
private static class SudokuSolver extends RecursiveTask<Integer> {
private static final long serialVersionUID = 8759452522630056046L;
private Sudoku state;
private int column;
private int row;
SudokuSolver(Sudoku state) {
this.state = state;
// These settings allow the search loop in compute() to increment first without asking questions about
// whether this cell has been checked yet.
column = -1;
row = 8;
}
SudokuSolver(Sudoku state, int column, int row) {
this.column = column;
this.row = row;
this.state = state;
}
@Override
protected Integer compute() {
int viableSolutions = 0;
if (state.isPlausible()) {
int originalColumn = column;
int originalRow = row;
do {
if (row + 1 >= 9) {
++column;
row = 0;
} else {
++row;
}
} while (column < 9 && state.get(column, row) != 0);
if (column >= 9) {
viableSolutions = 1;
} else {
List<SudokuSolver> solvers = new ArrayList<>();
for (int value = 1; value <= 9; ++value) {
Sudoku copy = new Sudoku(state);
copy.set(column, row, value);
solvers.add(new SudokuSolver(copy, column, row));
}
invokeAll(solvers);
for (SudokuSolver solver : solvers) {
viableSolutions += solver.join();
}
}
}
return viableSolutions;
}
}
}
由于该代码的时间需要多长时间来算的解决方案,输出可以不同,但我得到了
354
709.848410 ms
有在该方法中未在示例中提供使用的方法和字段。这使得这些其他方法可能会修改这些字段或调用其他方法,这使得解决您的问题变得更加困难。你能提供完整的课程吗? – sadakatsu
我不知道这是否会解决您的失败问题,但是产生多个求解器线程的循环似乎犯了一个可怕的错误。你创建一个你当前状态的副本,但是将你的内部状态传入'SudokuMulti'而不是副本!这意味着子进程正在修改调用者的状态。我相当肯定你需要这个块来像'Cella [] [] copy = createCopy();拷贝[I] [j]的.setCurrent(V); forkedThreads。添加(新的SudokuMulti(复制,i + 1,j).fork());' – sadakatsu
@sadakatsu完成,谢谢 –