//-----------------------------------------------------------------------------
// NQueens.java
// Solves the n-queens problem
//-----------------------------------------------------------------------------
import java.io.*;
import java.util.Scanner;

class NQueens{
   public void main(String[] args) throws IOException{
      if(args.length < 2){
       System.out.println("Usage: java –jar NQueens.jar <input file> <output file>");
       System.exit(1);
     }
      // open files
      Scanner in = new Scanner(new File(args[0]));
      PrintWriter out = new PrintWriter(new FileWriter(args[1]));

      String[] token;

      while( in.hasNextLine() ){
        // trim leading and trailing spaces, then add one trailing space so
        // split works on blank lines
        String line = in.nextLine().trim() + " ";

        // split line around white space
        token = line.split("\\s+");
        //if we dont have enough arguments to work from, cancel running.
        if(token.length%3 != 0){
         System.out.println("Please input a parameter divisible by three.");
         System.exit(1);
        }
      }
      //converts token into an int array
      int[] intoken = new int[token.length];
      for(int i = 0; i < 3; i++) {
        intoken[i] = Integer.parseInt(token[i]);
      }

      //determines how many times we're going to solve NQueens
      int val = intoken.length/3;
      for (int j = 0; j <= val;j++){}
      Queen[] solution = new Queen[intoken[0]]; //creates the solution array of length given

      //fills nQueens with 00s
      for (int i=0;i<solution.length;i++){
        solution[i] = new Queen(0,0);
       }

      //replaces the 0,0 with the column and row given
      solution[intoken[1]] = Queen(intoken[1],intoken[2]);
      int r = 0;
       if (nQueens(solution,r) == true) {
           String sol;
           for (int i = 0; i < solution.length;i++) {
              sol = "" + solution[i] + " ";
           }
           System.out.print(sol);
        }
        if (nQueens(solution,c,r) == false)
          System.out.print("Error");
   }

   boolean nQueens(Queen[] s, int r){ //takes in array of queens
      for (int i = 0; i < s.length){ //iteration to decide which column we're in
         if (i == s.length) //if we've reached the end, we return that this is capable
            return true;
          if (r == s.length) //if we've completed a column without being able to place a queen, return false
            return false;
        //  if (s[i] != (0,0))
         s[i] = Queen(i,r); //creates a new queen in the solutions array
         for (int i = 0;i < solution.length;i++){
          for (int j = 0;j < i;j++){ //ask about this logic
            if solution[i].isAttacking(solution[j]){
              r++;
              nQueens(s,r);
            }
          }
         }
         r = 0;
         i++;
         nQueens(s,r);
     }
  }
}


class Queen{
   int col;
   int row;
   public void Queen(int c,int r){ //constructor
      col = c;
      row = r;
   }
   boolean isAttacking(Queen q) {
      if (col==q.col || row == q.row) //horizontal and vertical check
         return true;
      if ((q.col + 1 == col && q.row + 1 ==row) || (q.col -1 == col && q.row -1 == row)) //diagonal check WIP
         return false;
   }
}