Sudoku Solver problem in the code

#1

hey i can able to resolve my error can you help me in resolving
#include
#include
using namespace std;
bool canPlace(int mat[][n],int i,int j,int n,int number){
for(int x=0;x<n;x++){
//Row column check
if(mat[x][j] == number || mat[i][x] == number){
return false;
}
}

int rn =sqrt(n);
int sx = (i/rn)*rn;
int sy = (j/rn)*rn;

for(int x = sx;x<sx+rn;x++){
    for(int y=sy;y<sy+rn;y++){
        if(mat[x][y] == number){
            return false;
        }
    }
}
return true;

}

bool SolveSudoku(int mat[][n],int i,int j,int n){
//base case
if(i==n){
//print the matrix
for(int i=0;i<n;i++){
for(int j=0;j<n;j++){
cout<<mat[i][j]<<" ";
}
cout<<endl;
}

    return true;
}

//column end 
if(j==n){
    SolveSudoku(mat,i+1,0,n);
}

//skipping the pre-filled cells;

if(mat[i][j] != 0){
    SolveSudoku(mat,i,j+1,n);
}

//recursive case
//placing the number where 0

for(int number=1;i<n;i++){
    if(canPlace(mat,i,j,n,number)){
        
        //assume 
        mat[i][j] = number;
        bool couldPlace = SolveSudoku(mat,i,j+1,n);

        if(couldPlace==true){
            return true;
        }
    }
}

//backtrack 
mat[i][j] = 0;
return false;

}

int main() {
int n;
cin>>n;
cout<<n<<" ";
int mat[n][n];

for(int i=0;i<n;i++){
	for(int j=0;j<n;j++){
		cin>>mat[i][j];
	}
}

//call SolveSudoku functio
SolveSudoku(mat,0,0,n);

return 0;

}

#2

I have edited your code, try to submit now,

#3

if i want to solve a sudoku of n = 18 then should it work ??
I am not get the solution well plz if you mark why you do that change in my code it will be helpful.

#4

This is only for 9x9 matrix only… You can try for 18x18 input as well, I only changed the matrix as mat[9][9], wherever it is present in your code, and also I have changed these in your code, as you forget to write return before making recursive calls…
if(j==n){
return SolveSudoku(mat,i+1,0,n);
}
if(mat[i][j] != 0){
return SolveSudoku(mat,i,j+1,n);
}

Rest code was alright…