restructure and add ipi texs

ws2019/ipi/uebungen/cpp_headers/Heap.hh

@@ -0,0 +1,54 @@
+template<class T>
+class Heap {
+public:
+  bool empty ();
+  void push (T x);
+  void pop ();
+  T top ();
+private:
+  std::vector<T> data;
+  void reheap (int i);
+} ;
+
+template<class T>
+void Heap<T>::push (T x) {
+  int i = data.size();
+  data.push_back(x);
+  while (i>0 && data[i]>data[(i-1)/2])
+    {
+      std::swap(data[i],data[(i-1)/2]);
+      i = (i-1)/2;
+    }
+}
+
+template <class T> 
+void Heap<T>::reheap (int i)  {
+  int n = data.size();
+  while (2*i+1<n)
+    {
+      int l = 2*i+1;
+      int r = l+1;
+      int k = ((r<n) && (data[r]>data[l])) ? r : l;
+      if (data[k]<=data[i]) break;
+      std::swap(data[k], data[i]);
+      i = k;
+    }
+}
+
+template<class T>
+void Heap<T>::pop () {
+  std::swap(data.front(), data.back());
+  data.pop_back();
+  reheap(0);
+}
+
+template<class T>
+T Heap<T>::top () {
+  return data[0];
+}
+
+template<class T>
+inline bool Heap<T>::empty () {
+  return data.size()==0;
+}
+