Commit of the provided classed for task number 3

src/main/java/provided/_11/_3/Item.java

@@ -0,0 +1,74 @@
+public class Item {
+	
+	private String name;
+	private int value;
+	private int weight;
+	
+	public Item(String name, int value, int weight) {
+		super();
+		this.name = name;
+		this.value = value;
+		this.weight = weight;
+	}
+	
+	public String getName() {
+		return name;
+	}
+	
+	public void setName(String name) {
+		this.name = name;
+	}
+	
+	public int getValue() {
+		return value;
+	}
+	
+	public void setValue(int value) {
+		this.value = value;
+	}
+	
+	public int getWeight() {
+		return weight;
+	}
+	
+	public void setWeight(int weight) {
+		this.weight = weight;
+	}
+
+	@Override
+	public String toString() {
+		return name;
+	}
+
+	@Override
+	public int hashCode() {
+		final int prime = 31;
+		int result = 1;
+		result = prime * result + ((name == null) ? 0 : name.hashCode());
+		result = prime * result + value;
+		result = prime * result + weight;
+		return result;
+	}
+
+	@Override
+	public boolean equals(Object obj) {
+		if (this == obj)
+			return true;
+		if (obj == null)
+			return false;
+		if (getClass() != obj.getClass())
+			return false;
+		Item other = (Item) obj;
+		if (name == null) {
+			if (other.name != null)
+				return false;
+		} else if (!name.equals(other.name))
+			return false;
+		if (value != other.value)
+			return false;
+		if (weight != other.weight)
+			return false;
+		return true;
+	}
+
+}

src/main/java/provided/_11/_3/Knapsack.java

@@ -0,0 +1,61 @@
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+
+public abstract class Knapsack {
+	
+	protected List<Item> candidates = new ArrayList<>();
+	protected int capacity;
+
+	public Knapsack(int capacity, Collection<Item> candidates) {
+		super();
+		this.capacity = capacity;
+		this.candidates.addAll(candidates);
+	}
+
+	public int getCapacity() {
+		return capacity;
+	}
+
+	public void setCapacity(int capacity) {
+		this.capacity = capacity;
+	}
+
+	public List<Item> getCandidates() {
+		return candidates;
+	}
+	
+	public abstract Selection pack();
+	
+	private static final int REPETITIONS = 5;
+	private static final int CAPACITY = 49;
+
+	public static void main(String[] args) {
+		List<Item> items = new ArrayList<>();
+		items.add(new Item("Banknote", 100, 1));
+		items.add(new Item("Goldbar", 1000, 30));
+		items.add(new Item("Diamond", 750, 5));
+		test("Recursive", new KnapsackRecursive(CAPACITY, items));
+		test("Greedy", new KnapsackGreedy(CAPACITY, items));
+		test("Dynamic Programming", new KnapsackDynamic(CAPACITY, items));
+	}
+	
+	private static void test(String title, Knapsack knapsack) {
+		System.out.print(title);
+		Selection result = null;
+		long totalNs = 0;
+		for (int i = 0; i < REPETITIONS; i++) {
+			long start = System.nanoTime();
+			result = knapsack.pack();
+			long stop = System.nanoTime();
+			totalNs += stop - start;
+			System.out.print(".");
+		}
+		System.out.println("\n\t" + result);
+		totalNs /= REPETITIONS;
+		long totalMs = totalNs / 1000000L;
+		System.out.println("\tTime required: " + totalNs + " ns (~ " + totalMs + " ms)");
+		System.out.println();
+	}
+
+}

src/main/java/provided/_11/_3/KnapsackDynamic.java

@@ -0,0 +1,17 @@
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.Map;
+
+public class KnapsackDynamic extends Knapsack {
+	
+	public KnapsackDynamic(int capacity, Collection<Item> candidates) {
+		super(capacity, candidates);
+	}
+
+	@Override
+	public Selection pack() {
+		//TODO: implement this
+		return new Selection();
+	}
+
+}

src/main/java/provided/_11/_3/KnapsackGreedy.java

@@ -0,0 +1,15 @@
+import java.util.Collection;
+
+public class KnapsackGreedy extends Knapsack {
+
+	public KnapsackGreedy(int capacity, Collection<Item> candidates) {
+		super(capacity, candidates);
+	}
+
+	@Override
+	public Selection pack() {
+		//TODO: implement this
+		return new Selection();
+	}
+
+}

src/main/java/provided/_11/_3/KnapsackRecursive.java

@@ -0,0 +1,15 @@
+import java.util.Collection;
+
+public class KnapsackRecursive extends Knapsack {
+
+	public KnapsackRecursive(int capacity, Collection<Item> candidates) {
+		super(capacity, candidates);
+	}
+
+	@Override
+	public Selection pack() {
+		//TODO: implement this
+		return new Selection();
+	}
+
+}

src/main/java/provided/_11/_3/Selection.java

@@ -0,0 +1,112 @@
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+public class Selection {
+	
+	private Map<Item, Integer> items = new HashMap<>();
+	private int value;
+	private int weight;
+	
+	public Selection() {
+		super();
+	}
+	
+	public Selection(Selection previous) {
+		super();
+		items.putAll(previous.items);
+		value = previous.value;
+		weight = previous.weight;
+	}
+	
+	public Selection(Selection previous, Item item) {
+		super();
+		items.putAll(previous.items);
+		value = previous.value;
+		weight = previous.weight;
+		add(item);
+	}
+	
+	private void add(Item item) {
+		items.put(item, getCount(item) + 1);
+		value += item.getValue();
+		weight += item.getWeight();
+	}
+	
+	public int getCount(Item item) {
+		Integer result = items.get(item);
+		if (result == null) {
+			result = 0;
+		}
+		return result;
+	}
+	
+	public Collection<Item> getItems() {
+		return items.keySet();
+	}
+	
+	public int getValue() {
+		return value;
+	}
+	
+	public void setValue(int value) {
+		this.value = value;
+	}
+	
+	public int getWeight() {
+		return weight;
+	}
+	
+	public void setWeight(int weight) {
+		this.weight = weight;
+	}
+
+	@Override
+	public String toString() {
+		StringBuilder b = new StringBuilder();
+		b.append("Value: ");
+		b.append(value);
+		b.append(", weight: ");
+		b.append(weight);
+		b.append(", items: ");
+		List<Item> list = new ArrayList<>(items.keySet());
+		list.sort((i1, i2) -> i1.getName().compareTo(i2.getName()));
+		for (int i = 0; i < list.size(); i++) {
+			b.append(items.get(list.get(i)));
+			b.append("x ");
+			b.append(list.get(i).getName());
+			if (i < list.size() - 1) {
+				b.append(", ");
+			}
+		}
+		return b.toString();
+	}
+
+	@Override
+	public int hashCode() {
+		final int prime = 31;
+		int result = 1;
+		result = prime * result + ((items == null) ? 0 : items.hashCode());
+		return result;
+	}
+
+	@Override
+	public boolean equals(Object obj) {
+		if (this == obj)
+			return true;
+		if (obj == null)
+			return false;
+		if (getClass() != obj.getClass())
+			return false;
+		Selection other = (Selection) obj;
+		if (items == null) {
+			if (other.items != null)
+				return false;
+		} else if (!items.equals(other.items))
+			return false;
+		return true;
+	}
+	
+}