import java.util.ArrayList;
import java.util.Collections;

public class ArrayListChallenge {
    public static void main(String[] args) {
        ArrayList<Integer> numbers = new ArrayList<>();
        Collections.addAll(numbers, 3, 1, 4, 1, 5, 9, 2, 6, 5);

        int result = 0;
        for (int i = 0; i < numbers.size(); i++) {
            if (i % 2 == 0) {
                result += numbers.get(i);
            } else {
                result -= numbers.get(i);
            }
        }

        System.out.println("Result: " + result);
    }
}

import java.util.IdentityHashMap;
import java.util.Map;

public class IdentityHashMapMethodsExample {
    public static void main(String[] args) {
        Map<String, String> identityMap = new IdentityHashMap<>();

        String key1 = new String("key");
        String key2 = new String("key");

        // Метод put
        identityMap.put(key1, "Value 1");
        identityMap.put(key2, "Value 2");

        // Метод get
        System.out.println("Value for key1: " + identityMap.get(key1)); // Output: Value 1
        System.out.println("Value for key2: " + identityMap.get(key2)); // Output: Value 2

        // Метод size
        System.out.println("Size of IdentityHashMap: " + identityMap.size()); // Output: 2

        // Метод containsKey
        System.out.println("Contains key1: " + identityMap.containsKey(key1)); // Output: true
        System.out.println("Contains new key: " + identityMap.containsKey(new String("key"))); // Output: false

        // Метод containsValue
        System.out.println("Contains Value 1: " + identityMap.containsValue("Value 1")); // Output: true

        // Метод remove
        identityMap.remove(key1);
        System.out.println("Size after removing key1: " + identityMap.size()); // Output: 1

        // Методы keySet, values, entrySet
        System.out.println("Keys: " + identityMap.keySet()); // Output: [key2]
        System.out.println("Values: " + identityMap.values()); // Output: [Value 2]
        System.out.println("Entries: " + identityMap.entrySet()); // Output: [key2=Value 2]
    }
}

public class VariableChallenge {
    public static void main(String[] args) {
        long a = 123456789012345L;
        boolean b = true;
        double c = 1.2345;

        double result = (b ? a * c : a / c) + (b && a > 1000000000 ? c : a);

        System.out.println("Result: " + result);
    }
}

private final Enum<?>[] keyUniverse;

keyUniverse = keyType.getEnumConstants();

private transient Object[] values;

values = new Object[keyUniverse.length];

enum Color {
    RED, GREEN, BLUE;
}

public class EnumMapExample {
    public static void main(String[] args) {
        EnumMap<Color, String> colorMap = new EnumMap<>(Color.class);

        colorMap.put(Color.RED, "Red Color");
        colorMap.put(Color.GREEN, "Green Color");
        colorMap.put(Color.BLUE, "Blue Color");

        for (Color color : colorMap.keySet()) {
            System.out.println(color + ": " + colorMap.get(color));
        }
    }
}

enum Day {
    MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, SATURDAY, SUNDAY;
}

public class EnumMapCounter {
    public static void main(String[] args) {
        EnumMap<Day, Integer> dayCount = new EnumMap<>(Day.class);

        // Инициализация счетчика для каждого дня недели
        for (Day day : Day.values()) {
            dayCount.put(day, 0);
        }

        // Увеличиваем счетчики для некоторых дней
        dayCount.put(Day.MONDAY, dayCount.get(Day.MONDAY) + 1);
        dayCount.put(Day.FRIDAY, dayCount.get(Day.FRIDAY) + 2);
        dayCount.put(Day.SUNDAY, dayCount.get(Day.SUNDAY) + 3);

        // Выводим результаты
        for (Day day : dayCount.keySet()) {
            System.out.println(day + ": " + dayCount.get(day));
        }
    }
}

private transient Object[] elementData;

private int size;

public ArrayList(int initialCapacity) {
    if (initialCapacity > 0) {
        this.elementData = new Object[initialCapacity];
    } else if (initialCapacity == 0) {
        this.elementData = {};
    } else {
        throw new IllegalArgumentException("Illegal Capacity: " + initialCapacity);
    }
}

public ArrayList() {
    this.elementData = DEFAULTCAPACITY_EMPTY_ELEMENTDATA;
}

import java.util.ArrayList;

public class ArrayListExample {
    public static void main(String[] args) {
        ArrayList<String> list = new ArrayList<>();

        // Добавление элементов
        list.add("Apple");
        list.add("Banana");
        list.add("Cherry");

        // Получение элементов
        System.out.println("First element: " + list.get(0)); // Apple

        // Удаление элемента
        list.remove("Banana");
        System.out.println("List after removal: " + list); // [Apple, Cherry]

        // Размер списка
        System.out.println("Size of list: " + list.size()); // 2
    }
}

import java.util.LinkedList;

public class LinkedListChallenge {
    public static void main(String[] args) {
        LinkedList<Integer> list = new LinkedList<>();
        list.add(5);
        list.add(15);
        list.add(25);
        list.add(35);
        list.add(45);

        int sum = 0;
        for (int i = 1; i < list.size(); i += 2) {
            sum += list.get(i);
        }

        list.add(1, sum);
        list.removeLast();
        list.addFirst(sum);

        int result = 1;
        for (int value : list) {
            result *= value;
        }

        System.out.println("Result: " + result);
    }
}