//-------------------------------------------------------------------------------
//  SudokuSolutionTest.java		author: Aaron Logan, 25 October 2006
//  This is a possible solution for program #4 from midterm #2 for ComS 207, F06.
//-------------------------------------------------------------------------------

public class Program4_v2
{
	public static void main(String[] args)
	{
		int[][] S = {{1,2,3,4,5,6,7,8,9},
						 {4,5,6,7,8,9,1,2,3},
						 {7,8,9,1,2,3,4,5,6},
						 {2,1,4,3,6,5,8,9,7},
						 {3,6,5,8,9,7,2,1,4},
						 {8,9,7,2,1,4,3,6,5},
						 {5,3,1,6,4,2,9,7,8},
						 {6,4,2,9,7,8,5,3,1},
						 {9,7,8,5,3,1,6,4,2}};
						 
		if (gridTest(S))
			System.out.println("That is a valid su-do-ku solution!");
		else
			System.out.println("That is NOT a valid su-do-ku solution.");
			
		int[][] S1 = {{1,2,3,4,5,6,7,8,9},
						  {2,3,4,5,6,7,8,9,1},
						  {3,4,5,6,7,8,9,1,2},
						  {4,5,6,7,8,9,1,2,3},
						  {5,6,7,8,9,1,2,3,4},
						  {6,7,8,9,1,2,3,4,5},
						  {7,8,9,1,2,3,4,5,6},
						  {8,9,1,2,3,4,5,6,7},
						  {9,1,2,3,4,5,6,7,8}};
		
		if (gridTest(S1))
			System.out.println("That is a valid su-do-ku solution!");
		else
			System.out.println("That is NOT a valid su-do-ku solution.");
	}
	
	//----------------------------------------------------------------------------
	//	gridTest method:
	//	This method determines if the given su-do-ku puzzle solution, which is
	// passed to the method as a 9x9 array, is valid. A solution is valid if each
	// of the digits 1-9 are located in each
	//		1) row
	//		2) column
	//		3) 3x3 subgrid
	//	without repetition.
	//----------------------------------------------------------------------------
	public static boolean gridTest(int[][] array)
	{
		boolean pass = true;
		int i, j, a, b, z, currentDigit;
		int[] rowTally = {0,0,0,0,0,0,0,0,0},
				colTally = {0,0,0,0,0,0,0,0,0},
				sqrTally = {0,0,0,0,0,0,0,0,0};
		
		for (i=0; i<9 && pass; i++){
			for (j=0; j<9 && pass; j++){
				/* Tally the number of occurences of each digit in each row */
				rowTally[array[i][j]-1]++;
				/* Tally the number of occrrences of each digit in each column */
				colTally[array[j][i]-1]++;
				/* If more than one occurence of a digit is found within a row
					or a column, then the given su-do-ku solution is invalid. */
				if (rowTally[array[i][j]-1] > 1 || colTally[array[j][i]-1] > 1)
					pass = false;
			}
			/* Re-zero the digit-tally arrays */
			for (z=0; z<9 && pass; z++){
				rowTally[z] = 0;
				colTally[z] = 0;
			}
		}
		
		/* This loop controls the horizontal subgrid number */
		for (a=0; a<3 && pass; a++)
			/* This loop controls the vertical subgrid number */
	   	for (b=0; b<3 && pass; b++){
				/* This loop cycles through the rows in the block */
				for (i=0; i<3 && pass; i++)
					/* This loop cycles through the columns in the block */
					for (j=0; j<3 && pass; j++){
						/* Tally the number of occrrences of each digit in each block */
						currentDigit = array[3*a + i][3*b + j];
						sqrTally[currentDigit - 1]++;
						/* If more than one occurence of a digit is found within
							the block, then the given su-do-ku solution is invalid. */
						if (sqrTally[currentDigit - 1] > 1)
							pass = false;
					}
			/* Re-zereo the digit-tally array */
			for (z=0; z<9 && pass; z++)
				sqrTally[z] = 0;
			}
		
		return pass;
	}
}