Initial commit for 11.3

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

@@ -0,0 +1,33 @@
+package _11._3;
+
+import provided._11._3.Item;
+import provided._11._3.Knapsack;
+import provided._11._3.Selection;
+
+import java.util.*;
+
+public class KnapsackDynamic extends Knapsack {
+	
+	public KnapsackDynamic(int capacity, Collection<Item> candidates) {
+		super(capacity, candidates);
+	}
+
+	@Override
+	public Selection pack() {
+		return this.pack(new Selection(), new HashMap<>());
+	}
+
+	private Selection pack(Selection me, Map<Integer, Selection> mem) {
+		return mem.computeIfAbsent(me.getWeight(), weight -> {
+			Collection<Selection> children = new ArrayList<>();
+			for(Item candidate : this.candidates) {
+				if(candidate.getWeight() + me.getWeight() <= this.capacity) {
+					children.add(pack(new Selection(me, candidate), mem));
+				}
+			}
+
+			return children.stream().max(Comparator.comparingDouble(Selection::getValue)).orElse(me);
+		});
+	}
+
+}

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

@@ -0,0 +1,34 @@
+package _11._3;
+
+import provided._11._3.Item;
+import provided._11._3.Knapsack;
+import provided._11._3.Selection;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Comparator;
+import java.util.List;
+
+public class KnapsackGreedy extends Knapsack {
+
+	// descending
+	protected final List<Item> orderedCandidates;
+
+	public KnapsackGreedy(int capacity, Collection<Item> candidates) {
+		super(capacity, candidates);
+		this.orderedCandidates = new ArrayList<>(this.candidates);
+		this.orderedCandidates.sort(Comparator.comparing(Item::getValue).reversed());
+	}
+
+	@Override
+	public Selection pack() {
+		Selection selection = new Selection();
+		for(Item candidate : this.orderedCandidates) {
+			while(candidate.getWeight() + selection.getWeight() <= this.capacity) {
+				selection = new Selection(selection, candidate);
+			}
+		}
+		return selection;
+	}
+
+}

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

@@ -0,0 +1,33 @@
+package _11._3;
+
+import provided._11._3.Item;
+import provided._11._3.Knapsack;
+import provided._11._3.Selection;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Comparator;
+
+public class KnapsackRecursive extends Knapsack {
+
+	public KnapsackRecursive(int capacity, Collection<Item> candidates) {
+		super(capacity, candidates);
+	}
+
+	@Override
+	public Selection pack() {
+		return this.pack(new Selection());
+	}
+
+	private Selection pack(Selection me) {
+		Collection<Selection> children = new ArrayList<>();
+		for(Item candidate : this.candidates) {
+			if(candidate.getWeight() + me.getWeight() <= this.capacity) {
+				children.add(pack(new Selection(me, candidate)));
+			}
+		}
+
+		return children.stream().max(Comparator.comparingDouble(Selection::getValue)).orElse(me);
+	}
+
+}

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

@@ -1,3 +1,5 @@
+package provided._11._3;
+
 public class Item {
 	
 	private String name;

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

@@ -1,3 +1,9 @@
+package provided._11._3;
+
+import _11._3.KnapsackDynamic;
+import _11._3.KnapsackGreedy;
+import _11._3.KnapsackRecursive;
+
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.List;

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

@@ -1,17 +0,0 @@
-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

@@ -1,15 +0,0 @@
-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

@@ -1,15 +0,0 @@
-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

@@ -1,3 +1,5 @@
+package provided._11._3;
+
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.HashMap;