I don't know how to fix this code for it to print a sudoku puzzle with it saving the solution of the puzzle as a corresponding array. The code is in Java.

public class Sudoku

$\{$

int$[]$mat$[]$;

int N; $//$number of columns$/$rows$.$

int SRN; $//$square root of N

int K; $//$No$.$Of missing digits

$//$Constructor

Sudoku$($int N$,$int K$)$

$\{$

this.N $=$N;

this.K $=$K;

$//$Compute square root of N

Double SRNd $=$Math$.$sqrt$($N$)$;

SRN $=$SRNd$.$intValue$()$;

mat $=$new int$[$N$][$N$]$;

$\}$

$//$Sudoku Generator

public void fillValues$()$

$\{$

$//$Fill the diagonal of SRN x SRN matrices

fillDiagonal$()$;

$//$Fill remaining blocks

fillRemaining$(0,$SRN$)$;

$//$Remove Randomly K digits to make game

removeKDigits$()$;

$\}$

$//$Fill the diagonal SRN number of SRN x SRN matrices

void fillDiagonal$()$

$\{$

for $($int i $=0$; ii$==$j

fillBox$($i$,$i$)$;

$\}$

$//$Returns false if given $3$x $3$block contains num.

boolean unUsedInBox$($int rowStart, int colStart, int num$)$

$\{$

for $($int i $=0$; i$=$N && i$=$N && j$>=$N$)$

return true;

if $($i $<$SRN$)$

$\{$

if $($j $<$SRN$)$

j $=$SRN;

$\}$

else if $($i $<$N$-$SRN$)$

$\{$

if $($j$==($int$)($i$/$SRN$)*$SRN$)$

j $=$j $+$SRN;

$\}$

else

$\{$

if $($j $==$N$-$SRN$)$

$\{$

i $=$i $+1$;

j $=0$;

if $($i$>=$N$)$

return true;

$\}$

$\}$

for $($int num $=1$; num$<=$N; num$++)$

$\{$

if $($CheckIfSafe$($i$,$j$,$num$))$

$\{$

mat$[$i$][$j$]=$num;

if $($fillRemaining$($i$,$j$+1))$

return true;

mat$[$i$][$j$]=0$;

$\}$

$\}$

return false;

$\}$

$//$Remove the K no$.$of digits to

$//$complete game

public void removeKDigits$()$

$\{$

int count $=$K;

while $($count $!=0)$

$\{$

int cellId $=$randomGenerator$($N$*$N$)-1$;

$//$System$.$out.println$($cellId$)$;

$//$extract coordinates i and j

int i $=($cellId$/$N$)$;

int j $=$cellId$\%$N;

$//$System$.$out.println$($i$+""+$j$)$;

if $($mat$[$i$][$j$]!=0)$

$\{$

count$--$;

mat$[$i$][$j$]=0$;

$\}$

$\}$

$\}$