Практика за 5ый урок.

Java4L5HW/src/alexrm84/Backpack.java

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+package alexrm84;
+
+import java.util.HashSet;
+
+public class Backpack {
+
+    private final int MAX_WEIGHT=20;
+    private int maxPrice=0;
+
+    private HashSet<Item> items =new HashSet<>();
+    private HashSet<Item> resultItems = new HashSet<>();
+
+
+    public static void main(String[] args) {
+        Backpack backpack =new Backpack();
+        backpack.start();
+        backpack.display();
+    }
+
+    public void start(){
+        items.add(new Item("Ручка", 5, 1));
+        items.add(new Item("Карандаш", 4, 1));
+        items.add(new Item("Учебник", 20, 10));
+        items.add(new Item("Тетрадь", 10, 5));
+        items.add(new Item("Обед", 15, 15));
+        selectionOfItemsSimple(items);
+    }
+
+    private int getCurrentWeight(HashSet<Item> newItems){
+        int temp=0;
+        for (Item item:newItems) {
+            temp+=item.getWeight();
+        }
+        return temp;
+    }
+
+    private int getCurrentPrice(HashSet<Item> newItems){
+        int temp=0;
+        for (Item item:newItems) {
+            temp+=item.getPrice();
+        }
+        return temp;
+    }
+
+    public void selectionOfItemsSimple(HashSet<Item> newItems){
+        if (newItems.size()==0){
+            return;
+        }
+        if (getCurrentWeight(newItems)<=MAX_WEIGHT){
+            int check=getCurrentPrice(newItems);
+            if (check>=maxPrice){
+                maxPrice=check;
+                resultItems=newItems;
+            }
+        }
+        for (Item item:newItems) {
+            HashSet<Item> newSet =new HashSet<>(newItems);
+            newSet.remove(item);
+            selectionOfItemsSimple(newSet);
+        }
+    }
+
+    private void display(){
+        System.out.println("Оптимальный состав предметов дающий "+maxPrice+" состоит из:");
+        for (Item item:resultItems) {
+            System.out.print(item.getName()+" ");
+        }
+    }
+}

Java4L5HW/src/alexrm84/Exponentiation.java

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+package alexrm84;
+
+public class Exponentiation {
+
+    public static void main(String[] args) {
+        System.out.println(getResult(5,3));
+        System.out.println(getResult(5,0));
+        System.out.println(getResult(5,-3));
+    }
+
+    public static double getResult(int number,int degree){
+        if (degree==0){
+            return 1;
+        }
+        if (degree<0){
+            return 1/getResult(number,Math.abs(degree));
+        }
+        return number*getResult(number,degree-1);
+    }
+}

Java4L5HW/src/alexrm84/Item.java

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+package alexrm84;
+
+public class Item {
+    private int price;
+    private int weight;
+    private String name;
+
+    public Item(String name, int price, int weight) {
+        this.price = price;
+        this.weight = weight;
+        this.name=name;
+    }
+
+    public int getPrice() {
+        return price;
+    }
+
+    public int getWeight() {
+        return weight;
+    }
+
+    public String getName() {
+        return name;
+    }
+}