5.3 java

import java.util.ArrayList;
import java.util.HashSet;
import java.util.Scanner;
import java.io.*;
import java.util.Set;

public class Main {
    private static final Scanner scanner = new Scanner(System.in);
    static Scanner fileScanner;

    public static void main (String[] args) {
        int num;
        int[] arr;
        System.out.println("Program generates all subsets of the set of n elements.");
        System.out.println("Enter type of input." + '\n' + "1 is console input, 0 is file input.");
        String path;
        boolean chose = choose();
        if (chose) {
            System.out.println("Input size of plurality:");
            num = inputArraySize();
            System.out.println("Input plurality elements:");
            arr = inputArray(num);
        } else {
            path = inputFilePath();
            num = inputSizeOfArrayFromFile(path);
            arr = inputArrayFile(path, num);
        }
        ArrayList <ArrayList<Integer>> subsets = getSubsets(arr);
        output(subsets);
    }

    private static boolean choose() {
        int inputNumber = 0;
        boolean isIncorrect;
        final int MIN_NUM = 0;
        final int MAX_NUM = 1;
        do {
            isIncorrect = false;
            try {
                inputNumber = Integer.parseInt(scanner.nextLine());
            } catch (Exception e) {
                isIncorrect = true;
                System.out.println("Please, enter a number.");
            }
            if (!isIncorrect && (inputNumber < MIN_NUM || inputNumber > MAX_NUM)) {
                System.out.println("You are out of input range!");
                isIncorrect = true;
            }
        } while (isIncorrect);
        return inputNumber == 1;
    }

    private static int inputData() {
        int n = 0;
        boolean isIncorrect;
        do {
            isIncorrect = false;
            try {
                n = Integer.parseInt(scanner.nextLine());
            } catch (Exception e) {
                isIncorrect = true;
                System.out.println("Please, enter a integer number:");
            }
        } while (isIncorrect);
        return n;
    }

    private static int inputArraySize() {
        boolean isIncorrect;
        final int MIN_SIZE = 1;
        final int MAX_SIZE = 10;
        int num;
        do {
            num = inputData();
            isIncorrect = false;
            if ((num < MIN_SIZE) || (num > MAX_SIZE)) {
                System.out.println("Array size should be in the range from 1 to 10:");
                isIncorrect = true;
            }
        } while (isIncorrect);
        return num;
    }

    private static int[] inputArray(int num) {
        int[] arr = new int[num];
        for (int i = 0; i < arr.length; i++)
            arr[i] = inputData();
        return arr;
    }

    private static String inputFilePath() {
        String path;
        boolean isIncorrect;
        do {
            isIncorrect = false;
            System.out.println("Input file path:");
            path = scanner.nextLine();
            File file = new File(path);
            if (!file.exists()) {
                System.out.println("Wrong way to file.");
                isIncorrect = true;
            }
            if (!file.canRead() && file.exists()) {
                System.out.println("Impossible to read a file.");
                isIncorrect = true;
            }
            if (!file.canWrite() && file.canRead()) {
                System.out.println("Impossible to write a file.");
                isIncorrect = true;
            }
        } while (isIncorrect);
        return path;
    }
    private static int inputSizeOfArrayFromFile(String path) {
        int num = 0;
        boolean isIncorrect;
        final int MIN = 1;
        final int MAX = 10;
        do {
            isIncorrect = false;
            try {
                fileScanner = new Scanner(new File(path));
                num = fileScanner.nextInt();
            } catch (Exception q) {
                isIncorrect = true;
                System.out.println("Check file.");
                path = inputFilePath();
            }
            if (!isIncorrect && ((num < MIN) || (num > MAX))) {
                isIncorrect = true;
                System.out.println("Array size should be in the range from 1 to 10:");
                path = inputFilePath();
            }
        } while (isIncorrect);
        return num;
    }

    private static int[] inputArrayFile(String path, int num) {
        boolean isIncorrect;
        int[] arr = new int[num];
        do {
            isIncorrect = false;
            try {
                fileScanner = new Scanner(new File(path));
                fileScanner.nextLine();
                for (int i = 0; (i < arr.length); i++) {
                    arr[i] = fileScanner.nextInt();
                }
            } catch (Exception q) {
                isIncorrect = true;
                System.out.println("Reading of array elements failed.");
                path = inputFilePath();
            }
        } while (isIncorrect);
        return arr;
    }

    public static int[] removeRepetitions (int[] set) {
        Set<Integer> integerSet = new HashSet<>();
        for (int i: set) {
            integerSet.add(i);
        }

        int i = 0;
        int[] newSet = new int[integerSet.size()];
        for (int element: integerSet)
            newSet[i++] = element;
        return newSet;
    }
    public static ArrayList <ArrayList<Integer>> getSubsets (int[] set) {
        set = removeRepetitions(set);
        ArrayList<ArrayList<Integer>> allSubsets = new ArrayList<>();
        int max = 1 << set.length;
        for (int i = 0; i < max; i++) {
            ArrayList<Integer> subset = new ArrayList<>();
            int k = i;
            int index = 0;
            while (k > 0) {
                if ((k & 1) == 1) {
                    subset.add(set[index]);
                }
                k >>= 1;
                index++;
            }
            allSubsets.add(subset);
        }
        return allSubsets;
    }
    public static void output (ArrayList<ArrayList<Integer>> allSubsets) {
        System.out.println("All plurality's subsets:");
        for (ArrayList<Integer> subset : allSubsets) {
            System.out.println(subset);
        }
    }

}