View difference between Paste ID: 2FR50GYr and h40qCYfd

 package com.company;
 
 import java.util.*;
 
 public class Sudoku {
     public static int[][] sudokuInDigits = new int[9][9]; //matricata kydeto se pazi sudokuto
     private static boolean solved = false;//uslovie za izlizane ot rekursiqta
     public static void main(String[] args) {
         Scanner in = new Scanner(System.in);
         String[][] sudoku = new String[9][9];
         int placesToFill = 0;
         for (int i = 0; i < sudoku.length; i++) {
             for (int j = 0; j < 1; j++) {
                 sudoku[i][j] = in.next();
                     for (int k = 0; k < 9; k++) {
                         //prevryshtane ot String kym int na vxoda
                         if (sudoku[i][k] != "-") {
                             int digit = sudoku[i][j].charAt(k) - '0';
                             if (digit > 0) {
                                 sudokuInDigits[i][k] = digit;
                             }
                             else {
                                 //dynoto na rekursiqta
                                 placesToFill++;
                             }
                         }
                     }
             }
         }
         solveSudoku(placesToFill, 0);
         //printirane na gotovoto sudoku
         for (int i = 0; i < sudokuInDigits.length; i++) {
             for (int j = 0; j < sudokuInDigits[i].length; j++) {
                 System.out.print(sudokuInDigits[i][j]);
             }
             System.out.println();
         }
     }
 
     private static void solveSudoku(int squaresLeft, int nextNumber) {
         if (squaresLeft == 0 || solved) {
             solved = true;
             return;
         }
         for (int i = 0; i < sudokuInDigits.length; i++) {
             for (int j = 0; j < sudokuInDigits[i].length; j++) {
                 //obxojdane na matricata za da vidim kyde lipsvat chisla
                 if (sudokuInDigits[i][j] == 0) {
                     for (int k = 1; k < 10; k++) {
                         //proverki za tova koe chislo lipsva i koe se sydyrja na syotvetniq red/kolona
                         //ili kvadratche
                         if (checkRow(k,i) == true && checkColumn(j,k) == true
                                 && checkSquare(i,k,j) == true) {
                             sudokuInDigits[i][j] = k;
                             squaresLeft--;
                             solveSudoku(squaresLeft,k + 1);
                             //neobxodimo za da moje da kato se vryshta rekursiqta
                             //da ne promenq tekushtoto systoqnie
                             if(solved)
                                 return;
                             //pri otkriti konflikti vyzstanovqvame predishnoto systoqnie
                             //na matricata
                             sudokuInDigits[i][j] = 0;
                             squaresLeft++;
                         }
                     }
                     return;
                 }
             }
         }
         return;
     }
 
     private static boolean checkRow(int candidate, int row) {
         //proverka za reda dali sydyrjda chisloto
         for (int col = 0; col < 9; col++ ) {
             if (sudokuInDigits[row][col] == candidate)
                 return false;
         }
         return true;
     }
 
     private static boolean checkColumn(int column, int candidate) {
         //proverka za kolonata dali sydyrja chisloto
         for (int row = 0; row < 9; row++ ) {
             if (sudokuInDigits[row][column] == candidate)
                 return false;
         }
         return true;
     }
 
     private static boolean checkSquare(int row, int candidate, int column) {
         //izchisleniq za tova kakvo e razstoqnieto ot [0,0] do [row,column]
         int colMultiplier = column / 3;
         int rowMultiplier = row / 3;
         int cellsInASquareSide = 3;
         //proverka na kvadratcheto
         for (int i = 0; i < 9; i++) {
             if (sudokuInDigits[i % 3 + rowMultiplier * cellsInASquareSide][i / 3 +
                         colMultiplier * cellsInASquareSide] == candidate) {
                 return false;
             }
         }
         return true;
     }
 }