8-Queens.java

import java.util.*;
import java.util.function.Supplier;
import javafx.util.Pair;

class Individual {

    boolean[][] gene;
    int number_of_attacks;
    Pair<Integer, Integer> subInterval;
    int fitness;
    final int number_of_queens = 8;

    public Individual() {

        number_of_attacks = 0;
        fitness = 0;
        subInterval = new Pair<>(0, 0);
        gene = new boolean[number_of_queens][number_of_queens];

    }

    public Individual(int number_of_attacks, int fitness, boolean[][] queens) {

        this.number_of_attacks = number_of_attacks;
        this.fitness = fitness;
        this.gene = queens;

    }

}

public class Queens {

    static int population_size = 7;

    static final int maxNumberOfClashes = 28;

    static float pro_mutation = 0.0005f;

    static ArrayList<Individual> population = new ArrayList<>();

    static ArrayList<Individual> fittest_individuals = new ArrayList<>();

    static final int number_of_queens = 8;

    static Random random = new Random();

    static int sumOfFit = 0;

    static void print_population() {

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

        population.stream().forEach((ind) -> {
            System.out.println("fitness:" + ind.fitness);
            System.out.println("from:" + ind.subInterval.getKey() + "\tto:" + ind.subInterval.getValue());
            for (boolean[] booleans : ind.gene) {
                System.out.println(Arrays.toString(booleans));
            }
            System.out.println("--------------------------------------------------------");

        });

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

    static void init_population() {

        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] = false;
                }

                queens[j][random.nextInt(number_of_queens)] = true;

            }

            population.add(new Individual(number_of_attacks(queens), fittnes(number_of_attacks(queens)), queens));

        }

    }

    static void subInterval(ArrayList<Individual> inds) {

        sumOfFit = population.stream().map((ind) -> ind.fitness).reduce(0, (a, b) -> a + b);

        int to = 0, from = 0;
        int i = 0;

        while (i < inds.size()) {

            to += inds.get(i).fitness;

            inds.get(i).subInterval = new Pair<>(from, to);
            from = to;
            i++;
        }

    }

    static int numberOfAttacksOfOneQueen(boolean[][] queens, Pair<Integer, Integer> pos) {

        int count = 0;

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

        //column
        for (boolean[] queen : queens) {
            if (queen[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 number_of_attacks(boolean[][] queens) {
        int count = 0;

        for (int i = 0; i < queens.length; i++) {
            label:
            for (int j = 0; j < queens[i].length; j++) {
                if (queens[i][j]) {
                    count += numberOfAttacksOfOneQueen(queens, new Pair<>(i, j));
                    continue label;
                }
            }

        }
        return count / 2;
    }

    static int fittnes(int count) {
        return maxNumberOfClashes - count;
    }

    static Pair<Individual, Individual> selection() {

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

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

        Individual father = new Individual();
        Individual mother = new Individual();

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

            Individual ind = population.get(i);

            if (rand_f >= ind.subInterval.getKey() && rand_f < ind.subInterval.getValue()) {
                father.fitness = ind.fitness;
                father.number_of_attacks = ind.number_of_attacks;

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

                    System.arraycopy(ind.gene[j], 0, father.gene[j], 0, ind.gene[j].length);

                }

//                continue;
            }
            if (rand_m >= ind.subInterval.getKey() && rand_m < ind.subInterval.getValue()) {

                mother.fitness = ind.fitness;
                mother.number_of_attacks = ind.number_of_attacks;

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

                    System.arraycopy(ind.gene[j], 0, mother.gene[j], 0, ind.gene[j].length);

                }

            }

        }

        return new Pair<>(father, mother);

    }

    static Pair<Individual, Individual> crossover(Pair<Individual, Individual> selectedParents) {

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

        int croosPoint = random.nextInt(number_of_queens);

        Individual father = selectedParents.getKey();
        Individual mother = selectedParents.getValue();

        boolean[][] father_cp = new boolean[number_of_queens][number_of_queens];
        boolean[][] mother_cp = new boolean[number_of_queens][number_of_queens];

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

            System.arraycopy(father.gene[i], 0, father_cp[i], 0, father.gene[i].length);
            System.arraycopy(mother.gene[i], 0, mother_cp[i], 0, mother.gene[i].length);

        }

        for (int i = croosPoint; i < number_of_queens; i++) {

            System.arraycopy(mother_cp[i], 0, father.gene[i], 0, mother_cp[i].length);
            System.arraycopy(father_cp[i], 0, mother.gene[i], 0, father_cp[i].length);
        }

        return selectedParents;
    }

    static Pair<Individual, Individual> mutation(Pair<Individual, Individual> parents) {

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

        Individual father = parents.getKey();
        Individual mother = parents.getValue();

        Supplier<Boolean> r = () -> random.nextFloat() < pro_mutation;

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

            if (random.nextInt(100) == 1) {
                Arrays.fill(father.gene[i], false);
                father.gene[i][random.nextInt(number_of_queens)] = true;
            }

        }

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

            if (r.get()) {
                Arrays.fill(mother.gene[i], false);
                mother.gene[i][random.nextInt(number_of_queens)] = true;
            }

        }

        father.number_of_attacks = number_of_attacks(father.gene);
        father.fitness = fittnes(father.number_of_attacks);

        mother.number_of_attacks = number_of_attacks(mother.gene);
        mother.fitness = fittnes(mother.number_of_attacks);

        return parents;
    }

    static void fittest() {

        for (int i = 0; i < population.size(); i++) {
            if (population.get(i).fitness == maxNumberOfClashes) {
                fittest_individuals.add(population.get(i));
            }
        }

    }

    static void printMatingPool(Pair<Individual, Individual> parents) {

        System.out.println("--------------------MatingPool-----------------");
        System.out.println("-------------------------------Father-------------------------------");
        for (boolean[] booleanses : parents.getKey().gene) {
            System.out.println(Arrays.toString(booleanses));
        }

        System.out.println("-------------------------------Mother-------------------------------");
        for (boolean[] booleanses : parents.getValue().gene) {
            System.out.println(Arrays.toString(booleanses));
        }
        System.out.println("-----------------------------------------------------------------");
    }

    static boolean check(Pair<Individual, Individual> pair) {

        for (int i = 0; i < pair.getKey().gene.length; i++) {

            boolean f = false;

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

                if (!pair.getKey().gene[i][j]) {
                    f = true;
                }

            }

            if (f) {
                return false;
            }
        }

        for (int i = 0; i < pair.getValue().gene.length; i++) {

            boolean f = false;

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

                if (!pair.getValue().gene[i][j]) {
                    f = true;
                }

            }

            if (f) {
                return false;
            }
        }

        return true;

    }

    public static void main(String[] args) {

        init_population();

        fittest();

        subInterval(population);

        if (!fittest_individuals.isEmpty()) {

            fittest_individuals.forEach((ind) -> {
                for (boolean[] booleanse : ind.gene) {
                    System.out.println(Arrays.toString(booleanse));
                }
                System.out.println("-------------------------------------");
            });
            return;
        }

        int gen = 0;
        /*
        System.out.println("----------------Population--size:" + population.size() + "--------------------------");
        print_population();
        System.out.println("-----------------------------------------");
        System.out.println("-----------------------Mate------------------");

        printMatingPool(selection());
         */

        while (fittest_individuals.isEmpty()) {

            System.out.println("----------------Population--size:" + population.size() + "--------------------------");
            print_population();
            System.out.println("-----------------------------------------");

            Pair<Individual, Individual> matingPool = selection();
            printMatingPool(matingPool);

            matingPool = crossover(matingPool);
            printMatingPool(matingPool);

            matingPool = mutation(matingPool);
            printMatingPool(matingPool);

            population.add(matingPool.getKey());
            population.add(matingPool.getValue());

            fittest();
            subInterval(population);

            System.out.println("gen:" + gen++);
        }

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

        fittest_individuals.forEach((ind) -> {
            for (boolean[] booleanse : ind.gene) {
                System.out.println(Arrays.toString(booleanse));
            }
            System.out.println("-------------------------------------");
        });

    }

}