data/train/rghvgrv/Simple-Programs/Java-Programs/suduko.java

public class suduko {

	static int N = 9;
	static boolean solveSuduko(int grid[][], int row,int col){
		if (row == N - 1 && col == N)
			return true;
		if (col == N) {
			row++;
			col = 0;
		}
		if (grid[row][col] != 0)
			return solveSuduko(grid, row, col + 1);

		for (int num = 1; num < 10; num++) {
			if (isSafe(grid, row, col, num)) {
				grid[row][col] = num;
				if (solveSuduko(grid, row, col + 1))
					return true;
			}
			grid[row][col] = 0;
		}
		return false;
	}
	static void print(int[][] grid)
	{
		for (int i = 0; i < N; i++) {
			for (int j = 0; j < N; j++)
				System.out.print(grid[i][j] + " ");
			System.out.println();
		}
	}
	static boolean isSafe(int[][] grid, int row, int col,
						int num)
	{
		for (int x = 0; x <= 8; x++)
			if (grid[row][x] == num)
				return false;
		for (int x = 0; x <= 8; x++)
			if (grid[x][col] == num)
				return false;
		int startRow = row - row % 3, startCol= col - col % 3;
		for (int i = 0; i < 3; i++)
			for (int j = 0; j < 3; j++)
				if (grid[i + startRow][j + startCol] == num)
					return false;
		return true;
	}

	// Driver Code
	public static void main(String[] args)
	{
		int grid[][] = { 
				{ 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 (solveSuduko(grid, 0, 0))
			print(grid);
		else
		System.out.println("No Solution exists");
	}
}