8-queens-selection.java

package pkg8.queens;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Random;
import javafx.util.Pair;

public class Queens {

    static int population_size = 4;

    static int maxNumberOfClashes = 7 * population_size;

    static ArrayList<Boolean[][]> population = new ArrayList<>();

    static ArrayList<Integer> fittneses = new ArrayList<>();

    static ArrayList<Pair<Integer, Integer>> pro = new ArrayList<>();

    static final int number_of_queens = 8;

    static Random random = new Random();

    static void print_population(){

        System.out.println("-----------------------------------------------");
        System.out.println("-----------------------------------------------");

        for (Boolean[][] booleanses : population) {
            for (Boolean[] booleanse : booleanses) {
                System.out.println(Arrays.toString(booleanse));
            }
            System.out.println("-----------------------------------------------");
        }

        System.out.println("-----------------------------------------------");
        System.out.println("-----------------------------------------------");
    }

    static void init_population_and_fitnes() {

        for (int i = 0; i < population_size; i++) {

            Boolean queens[][] = new Boolean[number_of_queens][number_of_queens];

            for (int j = 0; j < number_of_queens; j++) {

                for (int k = 0; k < number_of_queens; k++) {

                    queens[j][k] = random.nextBoolean();

                }
            }
            population.add(queens);

        }

        for (Boolean[][] booleans : population) {
            fittneses.add(fittnes(booleans));
        }

        int sum = 0, key = 0,i=0;

        while (i < fittneses.size()) {
            sum += fittneses.get(i++);

            pro.add(new Pair<>(key, sum));
            key=sum;

        }
    }

    static int numberOfAttacks(Boolean[][] queens, Pair<Integer, Integer> pos) {

        int count = 0;

        if (!queens[pos.getKey()][pos.getValue()]) {
            return count;
        }

        //column
        for (int j = 0; j < queens.length; j++) {

            if (queens[j][pos.getValue()]) {
                count++;
            }

        }
        //row
        for (int j = 0; j < queens.length; j++) {

            if (queens[pos.getKey()][j]) {
                count++;
            }

        }
        //left of principal
        for (int i = 0; i < queens.length; i++) {

            for (int j = 0; j < queens[i].length; j++) {

                if ((pos.getKey() + pos.getValue() == i + j) && queens[i][j] && pos.getKey() != i && pos.getValue() != j) {
                    count++;
                }

            }

        }
        //right of principal up -part
        for (int k = pos.getKey() - 1, z = pos.getValue() - 1; k >= 0 && z >= 0; k--, z--) {

            if (queens[k][z]) {
                count++;
            }

        }
        //right of principal down -part
        for (int k = pos.getKey() + 1, z = pos.getValue() + 1; k < queens.length && z < queens.length; k++, z++) {

            if (queens[k][z]) {
                count++;
            }

        }

        return count - 2;
    }

    static int fittnes(Boolean[][] queens) {

        int count = 0;

        for (int i = 0; i < queens.length; i++) {
            for (int j = 0; j < queens[i].length; j++) {

                count += numberOfAttacks(queens, new Pair<>(i, j));
            }

        }
        return maxNumberOfClashes - count / 2;
    }

    static Pair<Boolean[][],Boolean[][]> selection(){

        int sumOfFitness=fittneses.stream().reduce(0, (a,b)->a+b);

        int rand_f = random.nextInt(sumOfFitness);
        int rand_m = random.nextInt(sumOfFitness);

        Boolean[][] father=null,mother=null;

        for (int i = 0; i < pro.size(); i++) {

            if(rand_f>=pro.get(i).getKey()&&rand_f<=pro.get(i).getValue())
                father = population.get(i);
             if(rand_m>=pro.get(i).getKey()&&rand_m<=pro.get(i).getValue())
                mother = population.get(i);

        }

        return new Pair<>(father,mother);

    }

    public static void main(String[] args) {

        init_population_and_fitnes();

        //print_population();
/*
        for (Integer f : fittneses) {
            System.out.print(f+"\t");
        }
        System.out.println("");

        for (Pair<Integer, Integer> pair : pro) {
             System.out.println(pair + "\t");
        }
       */

        for (Boolean[] booleans : population.get(0)) {
                    System.out.println(Arrays.toString(booleans));

        }


        System.out.println(fittnes(population.get(0)));



    }

}