weitere Beispielprogramme 3.5.2018

20180503/2-3-4-tree-9.cpp

+#include <iostream>
+
+using namespace std;
+
+const int MaxLeaves = 4;
+const int MaxEntries = MaxLeaves - 1;
+
+template <typename TElement>
+class TTree
+{
+
+  struct TEntry
+  {
+    TElement Content;
+    bool empty;
+
+    TEntry ()
+    {
+      empty = true;
+    }
+  };
+
+  struct TLeaf
+  {
+    TEntry Entry[MaxEntries];
+    TLeaf *Child[MaxLeaves];
+
+    TLeaf ()
+    {
+      for (int i = 0; i < MaxLeaves; i++)
+        Child[i] = NULL;
+    }
+
+    void SetEntry (int i, TElement e)
+    {
+      Entry[i].Content = e;
+      Entry[i].empty = false;
+    }
+  };
+
+  TLeaf *Root;
+
+private:
+
+  void SplitLeaf (TLeaf *FullLeaf, TElement NewElement, TLeaf *&Left, TLeaf *&Right, TElement &Middle)
+  {
+    int i = 0;
+    while (i < MaxEntries && NewElement > FullLeaf->Entry[i].Content)
+      i++;
+    TElement Top;
+    if (i < MaxEntries)
+      {
+        Top = FullLeaf->Entry[MaxEntries - 1].Content;
+        for (int j = MaxEntries - 1; j > i; j--)
+          FullLeaf->Entry[j] = FullLeaf->Entry[j - 1];
+        FullLeaf->SetEntry (i, NewElement);
+      }
+    else
+      Top = NewElement;
+    // Achtung: Hier benutzen wir, daß MaxEntries = 3 ist!
+    Middle = FullLeaf->Entry[2].Content;
+    FullLeaf->Entry[2].empty = true;
+    Left = FullLeaf;
+    Right = new TLeaf ();
+    Right->SetEntry (0, Top);
+  }
+
+  void PrintLeaf (TLeaf *Leaf)
+  {
+    if (Leaf)
+      {
+        for (int i = 0; i < MaxEntries; i++)
+          {
+            PrintLeaf (Leaf->Child[i]);
+            if (!Leaf->Entry[i].empty)
+              cout << Leaf->Entry[i].Content << " ";
+          }
+        PrintLeaf (Leaf->Child[MaxLeaves - 1]);
+      }
+  }
+
+public:
+
+  TTree ()
+  {
+    Root = NULL;
+  }
+
+  void Insert (TElement e)
+  {
+    if (!Root)
+      Root = new TLeaf ();
+    if (Root->Entry[MaxEntries - 1].empty)
+      {
+        int i = 0;
+        while (i < MaxEntries && !Root->Entry[i].empty && e > Root->Entry[i].Content)
+          i++;
+        if (i < MaxEntries)
+          {
+            if (!Root->Entry[i].empty)
+              for (int j = MaxEntries - 1; j > i; j--)
+                Root->Entry[j] = Root->Entry[j - 1];
+            Root->SetEntry (i, e);
+          }
+      }
+    else
+      {
+        TLeaf *Left, *Right;
+        TElement Middle;
+        SplitLeaf (Root, e, Left, Right, Middle);  // "zerstört" Root
+        Root = new TLeaf ();
+        Root->SetEntry (0, Middle);
+        Root->Child[0] = Left;
+        Root->Child[1] = Right;
+      }
+  }
+
+  void Print ()
+  {
+    PrintLeaf (Root);
+    cout << endl;
+  }
+
+};
+
+int main ()
+{
+  TTree <int> t;
+  t.Insert (42);
+  t.Insert (13);
+  t.Insert (137);
+  t.Insert (7);
+  t.Print ();
+  return 0;
+}