// Press Shift twice to open the Search Everywhere dialog and type `show whitespaces`,
// then press Enter. You can now see whitespace characters in your code.
public class Main {
    public static long Fibonacci_Iter(int num){
        long smol = 1;
        long big = 1;
        long temp;

        while (1 < num){
            temp = smol;
            smol = big;
            big = big + temp;
            num--;
        }
        return big;
    }
    public static long Fibonacci_Rec(int num){

        // Inputqualität
        if(num < 0){
           System.out.println("Ungültiger Input");
           return 0;
       }

       if(num < 2){
           return 1;
       }

       return Fibonacci_Rec(num-2) + Fibonacci_Rec(num-1);
    }
    public static long Fibonacci_Round(int num){
        long result = 1;
        if(num==0 || num==1){return 1;}
        for(int i=1; i<num; i++){result = Math.round(result*1.61803398875);}
        return result;
    }
    public static void QueensPlace(int field[][],int row, int col){

        // block spaces
        for (int i=0; i<8; i++){
            // block row and col
            field[i][col]=3;
            field[row][i]=3;

            // block diagonals
            // Left 2 Right, Top 2 Bottom
            if (row - col + i < 8 && row - col + i >= 0) {
                field[row-col + i][i]=3;
            }

            // Left 2 Right, Bottom 2 Top
            if(row+i < 8 && row+i >=0 && col-i < 8 && col-i >=0){
                field[row+i][col-i]=3;
            }
            if(row-i < 8 && row-i >=0 && col+i < 8 && col+i >=0){
                field[row-i][col+i]=3;
            }
        }
        // place queen
        field[row][col]=1;
    }
    public static boolean QueensFree(int field[][], int row, int col){
        return field[row][col] == 0;
    }
    public static void QueensPrint(int field[][]){
        // print field
        System.out.println("---------------");
        for(int i=0; i<field.length; i++){
            for(int j=0; j<field[i].length; j++) {
                System.out.print(field[i][j]+" ");
            }
            System.out.println();
        }
        System.out.println("---------------");
        System.out.println();
    }
    public static int[][] QueensSetup(int rows, int cols){

        int field[][] = new int[rows][cols];
        for(int i = 0; i < rows-1; i++){
            for(int j = 0; j < cols-1; j++){
                field[i][j]=0;
            }
        }
    return field;
    }
    public static void QueensMain(){
        int rows=8;
        int cols=8;
        int start_queens=8;
        int queens = start_queens;
        int field[][] = QueensSetup(rows,cols);
        int wrong[][] = new int[8][8];


        while(queens>0){
            boolean full = true;
            for(int i=0;i<rows;i++){
                for(int j=0;j<cols;j++){
                    if(QueensFree(field,i,j)){
                        QueensPlace(field,i,j);
                        queens--;
                        full = false;
                    }
                }
            }
            System.out.println("Lösungsversuch: ");
            QueensPrint(field);
            if(full){

                // current Queens as wrong for next time
                 for (int i=0; i<8; i++){
                   for(int j=0; j<8; j++){
                       if(field[i][j]==1){
                           wrong[i][j]=3;
                       }
                   }
                 }
                 // reset
                 field = QueensSetup(rows,cols);
                 queens = start_queens;

                 // block earlier wrongs
                 for(int i = 0; i<8; i++){
                     for(int j = 0; j<8; j++){
                         if(wrong[i][j]==3){
                             field[i][j]=3;
                         }
                     }
                 }
                System.out.println("New Starting field: ");
                QueensPrint(field);
                 // aktuelle Positionen d Queens merken und sperren, rest reset
            }
        }
        System.out.println("Finale Lösung: ");
        QueensPrint(field);
    }

    public static void main(String[] args) {
         /*for(int i=0; i<4; i++) {
             System.out.println("i= "+i);
             System.out.println("Iter : " + Fibonacci_Iter(i));
             System.out.println("Rec  : " + Fibonacci_Rec(i));
             System.out.println("Round: " + Fibonacci_Round(i));
             System.out.println();
         }*/
        // ---------------------------------------------------------
        QueensMain();
        }
    }