Thread: Need help with this Sudoku code.

I can run the code but it does not solve, I can not figure it out. Thx

public class SudokuTestSolver {
int Unassigned = 0;
 
 
public boolean solveSudoku(int[][] grid) {
	int x = 0;
	int y = 0;
 
	// If there is no unassigned location, we are done
	if (!findUnassignedLocation(grid, x, y)) {
	   return true;
	}
 
	for (int num = 1; num <= 9; num++) {
 
		if (isSafe(grid, x, y, num)) {
 
			grid[x][y] = num;
 
			if (solveSudoku(grid)) {
				return true;
			}
 
			grid[x][y] = Unassigned;
		}
 
	}
	return false; 
}
 
 
 
public boolean findUnassignedLocation(int[][] grid, int x, int y) {
	for (int i = 0; i < 9; i++) {
		for (int j = 0; j < 9; j++) {
			if (grid[x][y] == 0) {
				return true;   
			}
		}
	}
	return false;
 
}
 
public boolean usedInRow(int[][] grid, int x, int num) {
	for (int y = 0; y < 9; y++) {
		if (grid[x][y] == num) {
			return true;
		}
	}
	return false;
}
 
 
 
public boolean usedInCol(int[][] grid, int y, int num) {
	for (int x = 0; x < 9; x++) {
		if (grid[x][y] == num) {
			return true;
		}
	}
	return false;
}
 
 
public boolean usedInBox(int[][] grid, int boxStartRow, int boxStartCol, int num) {
	for (int x = 0; x < 3; x++) {
		for (int y = 0; y < 3; y++) {
			if (grid[x + boxStartRow * 3][y + boxStartCol * 3] == num) {
				return true;
			}
		}
	}
	return false;
}
 
 
 
public boolean isSafe(int grid[][], int x, int y, int num) {
 
    return !usedInRow(grid, x, num) && 
           !usedInCol(grid, y, num) && 
           !usedInBox(grid, x - x%3 , y - y%3, num);
}
 
 
public void printGrid(int grid[][]) {
    for (int x = 0; x < 9; x++) {
       for (int y = 0; y < 9; y++)
          System.out.print(grid[x][y] + "  ");
        System.out.println();
    }
}
 
 
public static void main(String[] args) {
              int grid[][] = {{3, 0, 0,  0, 0, 0,  0, 0, 0},
                              {0, 0, 0,  0, 0, 0,  0, 0, 0},
                              {0, 0, 0,  1, 0, 0,  0, 0, 0},
 
                              {0, 0, 0,  0, 0, 0,  0, 0, 0},
                              {0, 0, 0,  0, 0, 0,  0, 0, 0},
                              {0, 0, 0,  0, 0, 0,  0, 0, 0},
 
                              {0, 0, 0,  0, 0, 0,  2, 0, 0},
                              {0, 0, 0,  0, 0, 0,  0, 0, 0},
                              {0, 0, 0,  0, 0, 0,  0, 0, 0}};
 
SudokuTestSolver s = new SudokuTestSolver();
 
 
 
int grid2[][] = new int[9][9];
 
 
for (int x = 0; x < 9; x++) {
   for (int y = 0; y < 9; y++) {
      grid2[x][y] = grid[x][y];
   }
}
 
if (s.solveSudoku(grid2) == true) {
 
   s.printGrid(grid2);
}
else {
   System.out.println("Can not be solved"); 
}  
 
}//end main
 
 
}//end class