#include <stdlib.h>
#include <stdio.h>

int** createSudoku(int emptyPositions)
{
	int i, j, temp;
	int removed;
	int **sudoku;
	
	sudoku = (int **) malloc(sizeof(int *) * 9);

	for (i=0; i<9; i++)
	{
		sudoku[i] = (int *) malloc(sizeof(int) * 9);
		for (j=0; j<9; j++)
		{
			temp = j + i*3 + (i/3 + 1) + 1;
			sudoku[i][j] = temp - (9 * (temp/9)) + 1;
		}
	}

	removed = 0;
	while (removed < emptyPositions)
	{
		i = rand() % 9;
		j = rand() % 9;

		if (sudoku[i][j] > 0)
		{
			sudoku[i][j] = -1;
			removed++;
		}
	}

	return sudoku;
}

void printSudoku(int** sudoku)
{
	int i,j;

	for (i=0; i<9; i++)
	{
		if (i%3 == 0)
		{
			printf("=============================\n");
		}
		printf("|| ");

		for (j=0; j<9; j++)
		{
			if (sudoku[i][j] > 0) {
				printf("%d",sudoku[i][j]);
			} else {
				printf(" ");
			}

			if ((j+1)%3 != 0) {
				printf(" ");
			} else {
				printf(" || ");
			}
		}
		printf("\n");
	}
	printf("=============================\n");
}

int main(int argc, char **argv)
{
	int emptyPositions = 0;

	if (argc > 1) {
		emptyPositions = atoi(argv[1]);
	}
	printSudoku(createSudoku(emptyPositions));

	return 0;
}