savepoint, changelog later..

include/crlib/cr-binheap.h

@@ -0,0 +1,141 @@
+//
+// Yet Another POD-Bot, based on PODBot by Markus Klinge ("CountFloyd").
+// Copyright (c) YaPB Development Team.
+//
+// This software is licensed under the BSD-style license.
+// Additional exceptions apply. For full license details, see LICENSE.txt or visit:
+//     https://yapb.ru/license
+//
+
+#pragma once
+
+#include <crlib/cr-array.h>
+
+CR_NAMESPACE_BEGIN
+
+// simple priority queue
+template <typename T> class BinaryHeap final : public DenyCopying {
+private:
+   Array <T> m_data;
+
+public:
+   explicit BinaryHeap () = default;
+
+   BinaryHeap (BinaryHeap &&rhs) noexcept : m_data (cr::move (rhs.m_data))
+   { }
+
+   ~BinaryHeap () = default;
+
+public:
+   template <typename U> bool push (U &&item) {
+      if (!m_data.push (cr::move (item))) {
+         return false;
+      }
+      size_t length = m_data.length ();
+
+      if (length > 1) {
+         percolateUp (length - 1);
+      }
+      return true;
+   }
+
+   template <typename ...Args> bool emplace (Args &&...args) {
+      if (!m_data.emplace (cr::forward <Args> (args)...)) {
+         return false;
+      }
+      size_t length = m_data.length ();
+
+      if (length > 1) {
+         percolateUp (length - 1);
+      }
+      return true;
+   }
+
+   const T &top () const {
+      return m_data[0];
+   }
+
+   T pop () {
+      if (m_data.length () == 1) {
+         return m_data.pop ();
+      }
+      auto key (cr::move (m_data[0]));
+
+      m_data[0] = cr::move (m_data.last ());
+      m_data.discard ();
+
+      percolateDown (0);
+      return key;
+   }
+
+public:
+   size_t length () const {
+      return m_data.length ();
+   }
+
+   bool empty () const {
+      return !m_data.length ();
+   }
+
+   void clear () {
+      m_data.clear ();
+   }
+
+private:
+   void percolateUp (size_t index) {
+      while (index != 0) {
+         size_t parent = this->parent (index);
+
+         if (m_data[parent] <= m_data[index]) {
+            break;
+         }
+         cr::swap (m_data[index], m_data[parent]);
+         index = parent;
+      }
+   }
+
+   void percolateDown (size_t index) {
+      while (this->left (index) < m_data.length ()) {
+         size_t best = this->left (index);
+
+         if (this->right (index) < m_data.length ()) {
+            size_t right_index = this->right (index);
+
+            if (m_data[right_index] < m_data[best]) {
+               best = right_index;
+            }
+         }
+
+         if (m_data[index] <= m_data[best]) {
+            break;
+         }
+         cr::swap (m_data[index], m_data[best]);
+
+         index = best;
+         best = this->left (index);
+      }
+   }
+
+private:
+   BinaryHeap &operator = (BinaryHeap &&rhs) noexcept {
+      if (this != &rhs) {
+         m_data = cr::move (rhs.m_data);
+      }
+      return *this;
+   }
+
+private:
+   static constexpr size_t left (size_t index) {
+      return index << 1 | 1;
+   }
+
+   static constexpr size_t right (size_t index) {
+      return ++index << 1;
+   }
+
+   static constexpr size_t parent (size_t index) {
+      return --index >> 1;
+   }
+};
+
+CR_NAMESPACE_END