我正在使用c＃尝试question。
class Solution
{
static int LEN = 9;
static int[] nums = new int[] {1, 2, 3, 4, 5, 6, 7, 8, 9};
public struct Sudoku
{
public int[,] grid;
public Sudoku(int[,] grid) : this()
{
this.n = n;
this.grid = new int[9, 9];
for (int r = 0; r < LEN; r++)
{
for (int c = 0; c < LEN; c++)
{
this.grid[r, c] = grid[r, c];
}
}
}
}
static bool isValid(int row, int col, int n, Sudoku s)
{
// check horizontally
for (int c = 0; c < LEN; c++)
{
if (s.grid[row, c] == n) return false;
}
// check vertically
for (int r = 0; r < LEN; r++)
{
if (s.grid[r, col] == n) return false;
}
// check box
for (int r = row / 3 * 3; r < row / 3 * 3 + 3; r++)
{
for (int c = col / 3 * 3; c < col / 3 * 3 + 3; c++)
{
if (s.grid[r, c] == n) return false;
}
}
return true;
}
static bool solve(Sudoku s)
{
for (int r = 0; r < LEN; r++)
{
for (int c = 0; c < LEN; c++)
{
if (s.grid[r, c] != 0) continue;
foreach (int n in nums)
{
if (isValid(r, c, n, s))
{
s.grid[r, c] = n;
print_sudoku(s);
if (solve(s)) return true;
}
}
return false;
}
}
return true;
}
}
起初，我尝试对多维数组使用递归，但是我发现当数独无法解决时，此行不会恢复我错误输入的数字：
if(solve(s)) return true;
所以，我改用一个结构，它是一个值类型，并按值传递。
但是，在Sudoku结构中，我使用的数组会再次导致相同的问题。
请给我一些指针，以便按值传递数字。
答案是每次循环后简单擦除数字
static bool solve(int[,] grid){
for (int r = 0; r < LEN; r++){
for (int c = 0; c < LEN; c++){
if (grid[r,c] != 0) continue;
foreach (int n in nums){
if (isValid(r, c, n, grid)) {
int[,] ngrid = new int[9,9];
for (int nr = 0; nr < LEN; nr++){
for (int nc = 0; nc < LEN; nc++){
ngrid[nr,nc] = grid[nr, nc];
}
}
ngrid[r, c] = n;
if(solve(ngrid)) return true;
}
}
return false;
}
}
print_sudoku(grid);
return true;
}
答案 0 :(得分：0)
请在下面查看我的解决方案。当无法解决时，我将一个空白放在一个单元格中
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
namespace Sudoku
{
public partial class Form1 : Form
{
SUDOKU sudoku = null;
public Form1()
{
InitializeComponent();
sudoku = new SUDOKU(this);
}
private void Solve_Click(object sender, EventArgs e)
{
SUDOKU.Solve();
}
private void Clear_Click(object sender, EventArgs e)
{
this.Controls.Remove(sudoku);
sudoku.Dispose();
sudoku = new SUDOKU(this);
}
}
public class SUDOKU : Panel
{
public const int TOP_MARGIN = 50;
public const int LEFT_MARGIN = 50;
static List<Cell> cells = new List<Cell>();
static List<List<Cell>> rows = null;
static List<List<Cell>> columns = null;
static List<List<Cell>> boxes = null;
public SUDOKU(Form form)
{
form.Controls.Add(this);
this.Left = LEFT_MARGIN;
this.Top = TOP_MARGIN;
this.Width = (2 * LEFT_MARGIN) + (9 * Cell.WIDTH);
this.Height = (2 * TOP_MARGIN) + (9 * Cell.HEIGHT);
rows = (new string('\0',9)).Select(x => new List<Cell>()).ToList();
columns = (new string('\0', 9)).Select(x => new List<Cell>()).ToList();
boxes = (new string('\0', 9)).Select(x => new List<Cell>()).ToList();
for (int i = 0; i < 81; i++)
{
Cell newCell = new Cell(i);
this.Controls.Add(newCell);
}
}
public static void Solve()
{
for (int i = 0; i < 81; i++)
{
if (cells[i].textBox.Text != "")
{
cells[i].value = int.Parse(cells[i].textBox.Text);
}
}
RecursiveSolve(0);
}
static Boolean RecursiveSolve(int index)
{
Boolean solved = false;
Cell cell = cells[index];
if (cell.value != null)
{
if (index == 80)
{
solved = true;
}
else
{
solved = RecursiveSolve(index + 1);
}
}
else
{
for (int i = 1; i <= 9; i++)
{
if (!rows[cell.row].Where(x => x.value == i).Any())
{
if (!columns[cell.column].Where(x => x.value == i).Any())
{
if (!boxes[cell.box].Where(x => x.value == i).Any())
{
cell.value = i;
cell.textBox.Text = i.ToString();
cell.textBox.SelectionAlignment = HorizontalAlignment.Center;
cell.textBox.SelectionFont = new Font("Ariel", 30);
if (index == 80)
{
solved = true;
}
else
{
solved = RecursiveSolve(index + 1);
if (solved)
{
break;
}
else
{
cell.value = null;
cell.textBox.Text = "";
}
}
}
}
}
}
}
return solved;
}
public class Cell : Panel
{
public const int WIDTH = 100;
public const int HEIGHT = 100;
public Dictionary<int, int> boxDict = new Dictionary<int, int>() {
{0,0}, {1,0},{2,0},{3,1},{4,1},{5,1},{6,2},{7,2},{8,2},
{9,0}, {10,0},{11,0},{ 12,1},{13,1},{14,1},{15,2},{16,2},{17,2},
{18,0}, {19,0},{20,0},{21,1},{22,1},{23,1},{24,2},{25,2},{26,2},
{27,3}, {28,3},{29,3},{30,4},{31,4},{32,4},{33,5},{34,5},{35,5},
{36,3}, {37,3},{38,3},{39,4},{40,4},{41,4},{42,5},{43,5},{44,5},
{45,3}, {46,3},{47,3},{48,4},{49,4},{50,4},{51,5},{52,5},{53,5},
{54,6}, {55,6},{56,6},{57,7},{58,7},{59,7},{60,8},{61,8},{62,8},
{63,6}, {64,6},{65,6},{66,7},{67,7},{68,7},{69,8},{70,8},{71,8},
{72,6}, {73,6},{74,6},{75,7},{76,7},{77,7},{78,8},{79,8},{80,8},
};
public int index = 0;
public int row = 0;
public int column = 0;
public int box = 0;
public int? value = null;
public RichTextBox textBox = new RichTextBox();
public Cell() { }
public Cell(int index)
{
cells.Add(this);
this.index = index;
this.row = index / 9;
this.column = index % 9;
this.box = boxDict[index];
this.Left = SUDOKU.LEFT_MARGIN + (column * WIDTH);
this.Top = SUDOKU.TOP_MARGIN + (row * HEIGHT);
this.Width = WIDTH;
this.Height = HEIGHT;
this.Controls.Add(textBox);
textBox.Left = 0;
textBox.Top = 0;
textBox.Width = WIDTH;
textBox.Height = HEIGHT;
textBox.SelectionAlignment = HorizontalAlignment.Center;
textBox.SelectionFont = new Font("Ariel", 30);
//textBox.Text = index.ToString();
textBox.Multiline = false;
rows[row].Add(this);
columns[column].Add(this);
boxes[box].Add(this);
}
}
public void Dispose()
{
cells = new List<Cell>();
rows = new List<List<Cell>>();
columns = new List<List<Cell>>(); ;
boxes = new List<List<Cell>>();
}
}
}