What is wrong with my code.why output is not correct

#1
#2

why no reply from any TA’s yet

#3

package Questions;
import java.util.Scanner;
public class sudoku_solver {
public static void main(String[] args)
{
Scanner obj =new Scanner(System.in);
int[][] board=new int[10][10];
int n=obj.nextInt();

	for(int i=0;i<n;i++)
	{
		for(int j=0;j<n;j++)
		{
			board[i][j]=obj.nextInt();
		}
	}
	int l=board.length;
	if(solveSudoku(board,l))
	{
		for(int i=0;i<n;i++)
		{
			for(int j=0;j<n;j++)
			{
				System.out.print(board[i][j]);
				System.out.print(" ");
			}
			System.out.println();

		}
	}
	else
	{
		System.out.println("no solution");
	}
}
public static boolean solveSudoku(int[][] board,int l)
{
	int row=-1;//where we will find our first empty cell
	int col=-1;
	boolean isEmpty=false;
	for(int i=0;i<l;i++)
	{
		for(int j=0;j<l;j++)
		{
			if(board[i][j]==0) // whether there is any empty cell
			{
				row=i;      
				col=j;
				isEmpty=true;// than set isEmpty to true
				break;
			}
		}
		if(isEmpty)// if you are having isEmpty value true that means now
			break;// you have to try to place a number .so break
	}
	if(!isEmpty) //if is empty value comes false that means your sudoku is solved.
	{
		return true;
	}

	for(int num=1;num<=9;num++)
	{
		if(isItSafe(board,row,col,num))// check whether num is safe to keep in row i and col j
		{
			board[row][col]=num;//if true place number
			if(solveSudoku(board,l))//call to function again to find another empty
			{
				return true;    
			}//space
			board[row][col]=0;
		}
	}
	return false;
}
public static boolean isItSafe(int[][] board,int row,int col, int num)
{
	for(int i=0;i<board.length;i++)// to check wether column is safe
	{
		if(board[i][col]==num)
		{
			return false;
		}

	}

	for(int i=0;i<board.length;i++)// to check whether row is safe
	{
		if(board[row][i]==num)
		{
			return false;
		}
	}
	int sqrt =(int)Math.sqrt(board.length);// to check wether box is safe
	int rowstart=row-row % sqrt;
	int colstart=col-col % sqrt;
	for(int i=rowstart;i<rowstart+sqrt;i++)
	{
		for(int j=colstart;j<colstart+sqrt;j++)
		{
			if(board[i][j]==num)
				return false;

		}
	}
	return true;
}

}

#4

your code is absolutely correct…just a small change make the board of size nXn instead of 10X10

#5

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