Initial commit for 6.1

src/main/java/_6/_1/HashMapMultiSet.java

@@ -0,0 +1,41 @@
+package _6._1;
+
+import java.util.HashMap;
+import java.util.Iterator;
+
+public class HashMapMultiSet<T> implements MultiSet<T> {
+    private HashMap<T,Integer> map = new HashMap<>();
+
+    public Iterator<T> iterator() {
+        return new HashMapMultiSetIterator();
+    }
+
+    public void add(T element) {
+        if (map.containsKey(element)) {
+            map.put(element,map.get(element)+1);
+        } else {
+            map.put(element,1);
+        }
+    }
+
+    public int count(T element) {
+        if (map.containsKey(element)) {
+            return map.get(element);
+        }
+        return 0;
+    }
+
+    class HashMapMultiSetIterator implements Iterator<T> {
+        @Override
+        public boolean hasNext() {
+            return map.keySet().iterator().hasNext();
+        }
+
+        @Override
+        public T next() {
+            return map.keySet().iterator().next();
+        }
+
+    }
+
+}

src/main/java/_6/_1/MultiSet.java

@@ -0,0 +1,14 @@
+package _6._1;
+
+/* a) REGENWETTER
+* Menge: {R,E,G,N,W,T}
+* Multimenge: {(R,2),(E,4),(G,1),(N,1),(W,1),(T,2)}
+*/
+
+public interface MultiSet<T> extends Iterable<T>{
+    void add(T element);
+
+    int count(T element);
+}
+
+