N-Queen Problem

PROBLEM :

The n-queens puzzle is the problem of placing n queens on an n×n chessboard such that no two queens attack each other. Given an integer n, print all distinct solutions to the n-queens puzzle. Each solution contains distinct board configurations of the n-queens’ placement, where the solutions are a permutation of [1,2,3..n] in increasing order, here the number in the ith place denotes that the ith-column queen is placed in the row with that number. For eg below figure represents a chessboard [3 1 4 2].

Input:
The first line of input contains an integer T denoting the no of test cases. Then T test cases follow. Each test case contains an integer n denoting the size of the chessboard.

Output:
For each test case, output your solutions on one line where each solution is enclosed in square brackets '[', ']' separated by a space . The solutions are permutations of {1, 2, 3 …, n} in increasing order where the number in the ith place denotes the ith-column queen is placed in the row with that number, if no solution exists print -1.

Constraints:
1<=T<=10
1<=n<=10

Example:
Input
2
1
4

Output:
[1 ]
[2 4 1 3 ] [3 1 4 2 ]
     
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SIMPLE c++ IMPLEMENTATION :
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#include<iostream>
using namespace std;
#define MAX 10

bool isSafe(int chess[MAX][MAX],int r,int c,int no)
{
    for(int i=0;i<c;i++)
        if(chess[r][i])
            return false ;
         
    for(int i=r-1,j=c-1;i>=0&&j>=0;i--,j--)
        if(chess[i][j])
            return false ;
         
    for(int i=r+1,j=c-1;i<no&&j>=0;i++,j--)
        if(chess[i][j])
            return false ;
         
    return true ;
}

void PrintBoard(int chess[MAX][MAX],int row)
{
    cout<<" [" ;
 
    for(int i=0;i<row;i++)
        for(int j=0;j<row;j++)
            if(chess[j][i])
                cout<<j+1<<" " ;
             
    cout<<"]" ;
}

void NQueen(int chess[MAX][MAX],int col,int row,bool *state)
{
    if(col==row)
    {
        PrintBoard(chess,row) ;
        (*state)=true ;
    }
 
    for(int i=0;i<row;i++)
    {
        if(isSafe(chess,i,col,row))
        {
            chess[i][col]=1 ;
            NQueen(chess,col+1,row,&(*state)) ;
            chess[i][col]=0 ;
        }
    }
}

int main()
{
int t ;
cin>>t ;
while(t--)
{
   int no ;
   cin>>no ;
 
   int chess[MAX][MAX] ;
 
   for(int i=0;i<no;i++)
       for(int j=0;j<no;j++)
           chess[i][j]=0 ;
         
   bool state=false ;
   NQueen(chess,0,no,&state) ;
   if(!state)
       cout<<-1 ;
     
   cout<<endl ;
}
return 0;
}

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