Admin: Created page with "Here’s a simple Sudoku Solver in C# using backtracking. It works on a standard 9x9 Sudoku grid. SudokuSolver using System; using S..."

2025-06-01T08:13:52Z

Created page with "Here’s a simple Sudoku Solver in C# using backtracking. It works on a standard 9x9 Sudoku grid. thumb|SudokuSolver using System; using S..."

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Here’s a simple Sudoku Solver in C# using backtracking. It works on a standard 9x9 Sudoku grid.

[[File:SudokuSolver.png|thumb|SudokuSolver]]

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
namespace sudoku_console
{
internal class Program
{
static int SIZE = 9;
public static void Main()
{
int[,] board = {
{5, 3, 0, 0, 7, 0, 0, 0, 0},
{6, 0, 0, 1, 9, 5, 0, 0, 0},
{0, 9, 8, 0, 0, 0, 0, 6, 0},
{8, 0, 0, 0, 6, 0, 0, 0, 3},
{4, 0, 0, 8, 0, 3, 0, 0, 1},
{7, 0, 0, 0, 2, 0, 0, 0, 6},
{0, 6, 0, 0, 0, 0, 2, 8, 0},
{0, 0, 0, 4, 1, 9, 0, 0, 5},
{0, 0, 0, 0, 8, 0, 0, 7, 9}
};
if (Solve(board))
{
PrintBoard(board);
Console.ReadLine();
}
else
{
Console.WriteLine("No solution exists.");
}
}
static bool Solve(int[,] board, bool isTimer = false)
{
for (int row = 0; row < SIZE; row++)
{
for (int col = 0; col < SIZE; col++)
{
if (board[row, col] == 0)
{
for (int num = 1; num <= 9; num++)
{
if (IsValid(board, row, col, num))
{
board[row, col] = num;
if (isTimer)
Thread.Sleep(1000);
if (Solve(board))
return true;
board[row, col] = 0; // backtrack
}
}
return false; // no valid number found
}
}
}
return true; // board is solved
}
static bool IsValid(int[,] board, int row, int col, int num)
{
for (int x = 0; x < SIZE; x++)
{
if (board[row, x] == num || board[row, x] == num)
return false;
}
for (int x = 0; x < SIZE; x++)
{
if (board[x, col] == num || board[x, col] == num)
return false;
}
int startRow = row / 3 * 3;
int startCol = col / 3 * 3;
for (int i = 0; i < 3; i++)
{
for (int j = 0; j < 3; j++)
{
if (board[startRow + i, startCol + j] == num)
return false;
}
}
return true;
}
static void PrintBoard(int[,] board)
{
for (int i = 0; i < SIZE; i++)
{
for (int j = 0; j < SIZE; j++)
{
Console.Write(board[i, j] + " ");
}
Console.WriteLine();
}
}
}
}

SudokuSolver - Revision history

Admin: Created page with "Here’s a simple Sudoku Solver in C# using backtracking. It works on a standard 9x9 Sudoku grid. SudokuSolver using System; using S..."