163 lines
4.5 KiB
C++
Executable File
163 lines
4.5 KiB
C++
Executable File
/****************************************************************************
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* VCGLib o o *
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* Visual and Computer Graphics Library o o *
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* _ O _ *
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* Copyright(C) 2004-2016 \/)\/ *
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* Visual Computing Lab /\/| *
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* ISTI - Italian National Research Council | *
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* \ *
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* All rights reserved. *
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* *
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* This program is free software; you can redistribute it and/or modify *
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* it under the terms of the GNU General Public License as published by *
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* the Free Software Foundation; either version 2 of the License, or *
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* (at your option) any later version. *
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* *
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* This program is distributed in the hope that it will be useful, *
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* but WITHOUT ANY WARRANTY; without even the implied warranty of *
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
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* GNU General Public License (http://www.gnu.org/licenses/gpl.txt) *
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* for more details. *
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* *
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****************************************************************************/
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#ifndef _PRIORITYQUEUE_H_
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#define _PRIORITYQUEUE_H_
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#include <algorithm>
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namespace vcg {
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/** Implements a bounded-size max priority queue using a heap
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*/
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template <typename Index, typename Weight>
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class HeapMaxPriorityQueue
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{
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struct Element
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{
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Weight weight;
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Index index;
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};
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struct
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{
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bool operator()(const Element& a, const Element& b) const
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{
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return a.weight < b.weight;
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}
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} lessElement;
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struct
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{
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bool operator()(const Element& a, const Element& b) const
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{
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return a.weight > b.weight;
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}
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} greaterElement;
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public:
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HeapMaxPriorityQueue(void)
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{
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mElements = 0;
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mMaxSize = 0;
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}
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~HeapMaxPriorityQueue()
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{
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if (mElements)
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delete[] mElements;
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}
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inline void setMaxSize(int maxSize)
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{
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if (mMaxSize!=maxSize)
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{
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mMaxSize = maxSize;
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delete[] mElements;
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mElements = new Element[mMaxSize];
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mpOffsetedElements = (mElements-1);
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}
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init();
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}
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inline void init() { mCount = 0; }
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inline bool isFull() const { return mCount == mMaxSize; }
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/** returns number of elements inserted in queue
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*/
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inline int getNofElements() const { return mCount; }
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inline Weight getWeight(int i) const { return mElements[i].weight; }
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inline Index getIndex(int i) const { return mElements[i].index; }
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inline Weight getTopWeight() const { return mElements[0].weight; }
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inline void insert(Index index, Weight weight)
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{
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if (mCount==mMaxSize)
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{
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if (weight<mElements[0].weight)
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{
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int j, k;
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j = 1;
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k = 2;
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while (k <= mMaxSize)
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{
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Element* z = &(mpOffsetedElements[k]);
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if ((k < mMaxSize) && (z->weight < mpOffsetedElements[k+1].weight))
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z = &(mpOffsetedElements[++k]);
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if(weight >= z->weight)
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break;
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mpOffsetedElements[j] = *z;
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j = k;
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k = 2 * j;
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}
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mpOffsetedElements[j].weight = weight;
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mpOffsetedElements[j].index = index;
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}
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}
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else
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{
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int i, j;
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i = ++mCount;
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while (i >= 2)
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{
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j = i >> 1;
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Element& y = mpOffsetedElements[j];
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if(weight <= y.weight)
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break;
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mpOffsetedElements[i] = y;
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i = j;
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}
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mpOffsetedElements[i].index = index;
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mpOffsetedElements[i].weight = weight;
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}
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}
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inline void sort(bool ascending = true)
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{
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if (ascending)
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std::sort(mElements, mElements + mCount, lessElement);
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else
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std::sort(mElements, mElements + mCount, greaterElement);
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}
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protected:
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int mCount;
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int mMaxSize;
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Element* mElements;
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Element* mpOffsetedElements;
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};
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}
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#endif
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