import java.util.LinkedHashMap;
import java.util.Map;

public class Task181125 {
    public static void main(String[] args) {
        Map<String, Integer> map = new LinkedHashMap<>(16, 0.75f, true);
        map.put("a", 1);
        map.put("b", 2);
        map.put("c", 3);
        
        map.get("a");
        map.get("b");
        map.put("d", 4);
        map.get("c");
        
        System.out.println(map.keySet());
    }
}

public class Task191125 {
    public static void main(String[] args) {
        Object obj = "42";

        String result = switch (obj) {
            case Integer i -> "Number: " + i;
            case String s when s.length() > 3 -> "Long string";
            case String ignored -> "Short string";
            default -> "Unknown";
        };

        System.out.println(result);
    }
}

public class Task201125 {
    public static void main(String arg) {
        System.out.println("Hello from single arg main");
    }

    public static void main(String[] args) {
        System.out.println("Hello from main");
    }
    
    public static void main() {
        System.out.println("Hello from parameterless main");
    }
}

public class Task211125 {
    public static void main(String[] args) {
        String s1 = "hello";
        String s2 = "he" + "llo";
        String s3 = "he";
        String s4 = "llo";
        String s5 = s3 + s4;
        
        System.out.println(s1 == s2);
        System.out.println(s1 == s5);
        System.out.println(s1.equals(s5));
        
        final String s6 = "he";
        final String s7 = "llo";
        String s8 = s6 + s7;
        System.out.println(s1 == s8);
    }
}

import java.util.LinkedList;

import static java.lang.Integer.valueOf;

public class Task241125 {
    public static void main(String[] args) {
        LinkedList<Integer> list = new LinkedList<>();
        list.add(1);
        list.add(2);
        list.add(3);

        list.remove(1);
        list.remove(valueOf(2));

        System.out.println(list.size());
        System.out.println(list.getFirst());
    }
}

import java.util.List;

public class Task251125 {
    public static void main(String[] args) {
        var list = List.of(1, 2, 3);
        var number = 10;
        var result = process(list, number);
        System.out.println(result);
    }
    
    static var process(List<Integer> list, int n) {
        var sum = 0;
        for (var item : list) {
            sum += item;
        }
        return sum * n;
    }
}

import java.util.ArrayList;
import java.util.List;

public class Task261125 {
    public static void main(String[] args) {
        List<Integer> list = new ArrayList<>();
        list.add(1);
        list.add(2);
        list.add(1, 3);
        list.add(0, 4);
        list.add(list.size(), 5);
        
        System.out.println(list);
    }
}