Solution For Eight Queen Problem

eightqueen.cpp

#include <iostream>
#include <vector>
#include <string>
#include <algorithm>

using namespace std;

void printChess(vector<vector<int> > &board)
{
  static int i = 1;
  cout << "****************************"<< i++ << "***************************************" << endl;
  for (int i=0; i<8; i++)
  {
    for (int j=0; j<8; j++)
    {
      cout << board[i][j] << "\t";
    }
    cout << endl;
  }


}

void placeQueen(vector<vector<int> > &board, int row)
{
  int mov_row[] = { 0,1,0,-1,-1,-1,1,1};
  int mov_col[] = { 1,0,-1,0,1,-1,-1,1};

  if (row == 8)
  {
    printChess(board);
    return;
  }

  for(int i=0; i<8; i++)
  {
    int flag_ignore = 0;
    int k=0;

    for(int j=0; j<8; j++)
    {
      int temp_row = row;
      int temp_col = i;
      while ((temp_row >=0) && (temp_row<8) && (temp_col>=0) && (temp_col<8))
      {
	if (board[temp_row][temp_col] == 8)
	{
	  flag_ignore=1;
	  break;
	}
	temp_row += mov_row[j];
	temp_col += mov_col[j];
      }

      if (flag_ignore)
	break;

    }
    if (!flag_ignore)
    {
      board[row][i] = 8;
      //cout << "Placed queen at " << row << "," << i << endl;
      placeQueen(board, row+1);
      board[row][i] = 1;
    }
  }
}


int main()
{

  vector<vector<int> > board(8,vector<int>(8,1));

  placeQueen(board,0);

  return 0;
}