deba@1186: /* -*- C++ -*-
deba@1186:  * src/lemon/bin_heap.h - Part of LEMON, a generic C++ optimization library
deba@1186:  *
deba@1186:  * Copyright (C) 2005 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
deba@1186:  * (Egervary Combinatorial Optimization Research Group, EGRES).
deba@1186:  *
deba@1186:  * Permission to use, modify and distribute this software is granted
deba@1186:  * provided that this copyright notice appears in all copies. For
deba@1186:  * precise terms see the accompanying LICENSE file.
deba@1186:  *
deba@1186:  * This software is provided "AS IS" with no warranty of any kind,
deba@1186:  * express or implied, and with no claim as to its suitability for any
deba@1186:  * purpose.
deba@1186:  *
deba@1186:  */
deba@1186: 
deba@1186: #ifndef LEMON_RADIX_HEAP_H
deba@1186: #define LEMON_RADIX_HEAP_H
deba@1186: 
deba@1186: ///\ingroup auxdat
deba@1186: ///\file
deba@1186: ///\brief Radix Heap implementation.
deba@1186: ///\todo It should be documented.
deba@1186: 
deba@1186: #include <vector>
deba@1186: #include <lemon/error.h>
deba@1186: 
deba@1186: namespace lemon {
deba@1186: 
deba@1186:   /// \addtogroup auxdat
deba@1186:   /// @{
deba@1186: 
deba@1205:   /// A Radix Heap implementation.
deba@1186:   
deba@1186:   ///\todo Please document...
deba@1186:   ///
deba@1186:   ///\sa BinHeap
deba@1186:   ///\sa Dijkstra
deba@1186: 
deba@1186:   class UnderFlowPriorityException : public RuntimeError {
deba@1186:   public:
deba@1186:     virtual const char* exceptionName() const {
deba@1186:       return "lemon::UnderFlowPriorityException";
deba@1186:     }  
deba@1186:   };
deba@1186: 
deba@1186:   template <typename _Item, typename _ItemIntMap>
deba@1186:   class RadixHeap {
deba@1186: 
deba@1186:   public:
deba@1186:     typedef _Item Item;
deba@1186:     // FIXME: stl-ben nem ezt hivjak value_type -nak, hanem a kovetkezot...
deba@1186:     typedef int Prio;
deba@1186:     typedef _ItemIntMap ItemIntMap;
deba@1186: 
deba@1186:     /**
deba@1186:      * Each Item element have a state associated to it. It may be "in heap",
deba@1186:      * "pre heap" or "post heap". The later two are indifferent from the
deba@1186:      * heap's point of view, but may be useful to the user.
deba@1186:      *
deba@1186:      * The ItemIntMap _should_ be initialized in such way, that it maps
deba@1186:      * PRE_HEAP (-1) to any element to be put in the heap...
deba@1186:      */
deba@1186:     ///\todo it is used nowhere
deba@1186:     ///
deba@1186:     enum state_enum {
deba@1186:       IN_HEAP = 0,
deba@1186:       PRE_HEAP = -1,
deba@1186:       POST_HEAP = -2
deba@1186:     };
deba@1186: 
deba@1186:   private:
deba@1186:     
deba@1186:     struct RadixItem {
deba@1186:       int prev, next, box;
deba@1186:       Item item;
deba@1186:       int prio;
deba@1186:       RadixItem(Item _item, int _prio) : item(_item), prio(_prio) {}
deba@1186:     };
deba@1186: 
deba@1186:     struct RadixBox {
deba@1186:       int first;
deba@1186:       int min, size;
deba@1186:       RadixBox(int _min, int _size) : first(-1), min(_min), size(_size) {}
deba@1186:     };
deba@1186: 
deba@1186:     std::vector<RadixItem> data;
deba@1186:     std::vector<RadixBox> boxes;
deba@1186: 
deba@1186:     ItemIntMap &iim;
deba@1186: 
deba@1186: 
deba@1186:   public:
deba@1186:     ///\e
deba@1186:     explicit RadixHeap(ItemIntMap &_iim) : iim(_iim) {
deba@1186:       boxes.push_back(RadixBox(0, 1));
deba@1186:       boxes.push_back(RadixBox(1, 1));
deba@1186:     }
deba@1186: 
deba@1186:     ///\e
deba@1186:     RadixHeap(ItemIntMap &_iim, int capacity) : iim(_iim) {
deba@1186:       boxes.push_back(RadixBox(0, 1));
deba@1186:       boxes.push_back(RadixBox(1, 1));
deba@1186:       while (upper(boxes.back(), capacity)) {
deba@1186: 	extend();
deba@1186:       }
deba@1186:     }
deba@1186: 
deba@1186:     ///\e
deba@1186:     int size() const { return data.size(); }
deba@1186:     ///\e
deba@1186:     bool empty() const { return data.empty(); }
deba@1186: 
deba@1186:   private:
deba@1186: 
deba@1186:     bool upper(int box, Prio prio) {
deba@1186:       return prio < boxes[box].min;
deba@1186:     }
deba@1186: 
deba@1186:     bool lower(int box, Prio prio) {
deba@1186:       return prio >= boxes[box].min + boxes[box].size;
deba@1186:     }
deba@1186: 
deba@1186:     /// \brief Remove item from the box list.
deba@1186:     void remove(int index) {
deba@1186:       if (data[index].prev >= 0) {
deba@1186: 	data[data[index].prev].next = data[index].next;
deba@1186:       } else {
deba@1186: 	boxes[data[index].box].first = data[index].next;
deba@1186:       }
deba@1186:       if (data[index].next >= 0) {
deba@1186: 	data[data[index].next].prev = data[index].prev;
deba@1186:       }
deba@1186:     }
deba@1186: 
deba@1186:     /// \brief Insert item into the box list.
deba@1186:     void insert(int box, int index) {
deba@1186:       if (boxes[box].first == -1) {
deba@1186: 	boxes[box].first = index;
deba@1186: 	data[index].next = data[index].prev = -1;
deba@1186:       } else {
deba@1186: 	data[index].next = boxes[box].first;
deba@1186: 	data[boxes[box].first].prev = index;
deba@1186: 	data[index].prev = -1;
deba@1186: 	boxes[box].first = index;
deba@1186:       }
deba@1186:       data[index].box = box;
deba@1186:     }
deba@1186: 
deba@1186:     /// \brief Add a new box to the box list.
deba@1186:     void extend() {
deba@1186:       int min = boxes.back().min + boxes.back().size;
deba@1186:       int size = 2 * boxes.back().size;
deba@1186:       boxes.push_back(RadixBox(min, size));
deba@1186:     }
deba@1186: 
deba@1186:     /// \brief Move an item up into the proper box.
deba@1186:     void bubble_up(int index) {
deba@1205:       if (!lower(data[index].box, data[index].prio)) return;
deba@1186:       remove(index);
deba@1186:       int box = findUp(data[index].box, data[index].prio);
deba@1186:       insert(box, index);      
deba@1186:     }
deba@1186: 
deba@1186:     /// \brief Find up the proper box for the item with the given prio.
deba@1186:     int findUp(int start, int prio) {
deba@1186:       while (lower(start, prio)) {
deba@1186: 	if (++start == (int)boxes.size()) {
deba@1186: 	  extend();
deba@1186: 	}
deba@1186:       }
deba@1186:       return start;
deba@1186:     }
deba@1186: 
deba@1186:     /// \brief Move an item down into the proper box.
deba@1186:     void bubble_down(int index) {
deba@1186:       if (!upper(data[index].box, data[index].prio)) return;
deba@1186:       remove(index);
deba@1186:       int box = findDown(data[index].box, data[index].prio);
deba@1186:       insert(box, index);
deba@1186:     }
deba@1186: 
deba@1186:     /// \brief Find up the proper box for the item with the given prio.
deba@1186:     int findDown(int start, int prio) {
deba@1186:       while (upper(start, prio)) {
deba@1186: 	if (--start < 0) throw UnderFlowPriorityException();
deba@1186:       }
deba@1186:       return start;
deba@1186:     }
deba@1186: 
deba@1186:     /// \brief Find the first not empty box.
deba@1186:     int findFirst() {
deba@1186:       int first = 0;
deba@1186:       while (boxes[first].first == -1) ++first;
deba@1186:       return first;
deba@1186:     }
deba@1186: 
deba@1186:     /// \brief Gives back the minimal prio of the box.
deba@1186:     int minValue(int box) {
deba@1186:       int min = data[boxes[box].first].prio;
deba@1186:       for (int k = boxes[box].first; k != -1; k = data[k].next) {
deba@1186: 	if (data[k].prio < min) min = data[k].prio;
deba@1186:       }
deba@1186:       return min;
deba@1186:     }
deba@1186: 
deba@1186:     /// \brief Rearrange the items of the heap and makes the 
deba@1186:     /// first box not empty.
deba@1186:     void moveDown() {
deba@1186:       //      print(); printf("moveDown\n"); fflush(stdout);       
deba@1186:       int box = findFirst();
deba@1186:       if (box == 0) return;
deba@1186:       int min = minValue(box);
deba@1186:       for (int i = 0; i <= box; ++i) {
deba@1186: 	boxes[i].min = min;
deba@1186: 	min += boxes[i].size;
deba@1186:       }
deba@1186:       int curr = boxes[box].first, next;
deba@1186:       while (curr != -1) {
deba@1186: 	next = data[curr].next;
deba@1186: 	bubble_down(curr);
deba@1186: 	curr = next;
deba@1186:       }      
deba@1186:     }
deba@1186: 
deba@1186:     void relocate_last(int index) {
deba@1186:       if (index != (int)data.size() - 1) {
deba@1186: 	data[index] = data.back();
deba@1186: 	if (data[index].prev != -1) {
deba@1186: 	  data[data[index].prev].next = index;
deba@1186: 	} else {
deba@1186: 	  boxes[data[index].box].first = index;
deba@1186: 	}
deba@1186: 	if (data[index].next != -1) {
deba@1186: 	  data[data[index].next].prev = index;
deba@1186: 	}
deba@1186: 	iim[data[index].item] = index;
deba@1186:       }
deba@1186:       data.pop_back();
deba@1186:     }
deba@1186: 
deba@1186:   public:
deba@1186: 
deba@1186:     ///\e
deba@1186:     void push(const Item &i, const Prio &p) {
deba@1186:       fflush(stdout);
deba@1186:       int n = data.size();
deba@1186:       iim.set(i, n);
deba@1186:       data.push_back(RadixItem(i, p));
deba@1186:       while (lower(boxes.size() - 1, p)) {
deba@1186: 	extend();
deba@1186:       }
deba@1186:       int box = findDown(boxes.size() - 1, p);
deba@1186:       insert(box, n);
deba@1186:       //      printf("Push %d\n", p);
deba@1186:       //print();
deba@1186:     }
deba@1186: 
deba@1186:     ///\e
deba@1186:     Item top() const {
deba@1186:       //      print(); printf("top\n");  fflush(stdout);
deba@1186:       const_cast<RadixHeap<Item, ItemIntMap>*>(this)->moveDown();
deba@1186:       return data[boxes[0].first].item;
deba@1186:       //      print(); printf("top_end\n");  fflush(stdout);
deba@1186:     }
deba@1186: 
deba@1186:     /// Returns the prio of the top element of the heap.
deba@1186:     Prio prio() const {
deba@1186:       //      print(); printf("prio\n"); fflush(stdout);
deba@1186:       const_cast<RadixHeap<Item, ItemIntMap>*>(this)->moveDown();
deba@1186:       return data[boxes[0].first].prio;
deba@1186:      }
deba@1186: 
deba@1186:     ///\e
deba@1186:     void pop() {
deba@1186:       //      print(); printf("pop\n"); fflush(stdout);
deba@1186:       moveDown();
deba@1186:       int index = boxes[0].first;
deba@1186:       iim[data[index].item] = POST_HEAP;
deba@1186:       remove(index);
deba@1186:       relocate_last(index);
deba@1186:       //      printf("Pop \n");
deba@1186:       //print();
deba@1186:     }
deba@1186: 
deba@1186:     ///\e
deba@1186:     void erase(const Item &i) {
deba@1186:       int index = iim[i];
deba@1186:       iim[i] = POST_HEAP;
deba@1186:       remove(index);
deba@1186:       relocate_last(index);
deba@1186:    }
deba@1186: 
deba@1186:     ///\e
deba@1186:     Prio operator[](const Item &i) const {
deba@1186:       int idx = iim[i];
deba@1186:       return data[idx].prio;
deba@1186:     }
deba@1186: 
deba@1186:     ///\e
deba@1186:     void set(const Item &i, const Prio &p) {
deba@1186:       int idx = iim[i];
deba@1186:       if( idx < 0 ) {
deba@1186: 	push(i, p);
deba@1186:       }
deba@1186:       else if( p >= data[idx].prio ) {
deba@1186: 	data[idx].prio = p;
deba@1186: 	bubble_up(idx);
deba@1186:       } else {
deba@1186: 	data[idx].prio = p;
deba@1186: 	bubble_down(idx);
deba@1186:       }
deba@1186:     }
deba@1186: 
deba@1186:     ///\e
deba@1186:     void decrease(const Item &i, const Prio &p) {
deba@1186:       //      print(); printf("decrease\n"); fflush(stdout);
deba@1186:       int idx = iim[i];
deba@1186:       data[idx].prio = p;
deba@1186:       bubble_down(idx);
deba@1186:     }
deba@1186: 
deba@1186:     ///\e
deba@1186:     void increase(const Item &i, const Prio &p) {
deba@1186:       int idx = iim[i];
deba@1186:       data[idx].prio = p;
deba@1186:       bubble_up(idx);
deba@1186:     }
deba@1186: 
deba@1186:     ///\e
deba@1186:     state_enum state(const Item &i) const {
deba@1186:       int s = iim[i];
deba@1186:       if( s >= 0 ) s = 0;
deba@1186:       return state_enum(s);
deba@1186:     }
deba@1186: 
deba@1205: //     void print() const {
deba@1205: //       for (int i = 0; i < boxes.size(); ++i) {
deba@1205: // 	printf("(%d, %d) ", boxes[i].min, boxes[i].size);
deba@1205: // 	for (int k = boxes[i].first; k != -1; k = data[k].next) {
deba@1205: // 	  printf("%d ", data[k].prio);
deba@1205: // 	}
deba@1205: // 	printf("\n");
deba@1205: //       }
deba@1205: //       fflush(stdout);
deba@1205: //     }
deba@1186: 
deba@1186:   }; // class RadixHeap
deba@1186: 
deba@1186: 
deba@1186:   ///@}
deba@1186: 
deba@1186: } // namespace lemon
deba@1186: 
deba@1186: #endif // LEMON_RADIX_HEAP_H