115 lines
3.4 KiB
C++
115 lines
3.4 KiB
C++
// Ryzom - MMORPG Framework <http://dev.ryzom.com/projects/ryzom/>
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// Copyright (C) 2010 Winch Gate Property Limited
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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 Affero General Public License as
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// published by the Free Software Foundation, either version 3 of the
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// License, or (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 Affero General Public License for more details.
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//
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// You should have received a copy of the GNU Affero General Public License
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// along with this program. If not, see <http://www.gnu.org/licenses/>.
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#ifndef RYAI_KNAPSACK_SOLVER_H
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#define RYAI_KNAPSACK_SOLVER_H
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//////////////////////////////////////////////////////////////////////////////
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// IKnapsackContext //
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//////////////////////////////////////////////////////////////////////////////
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class IKnapsackContext
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{
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public:
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virtual ~IKnapsackContext() { }
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virtual float weight(size_t i) = 0;
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virtual float value(size_t i) = 0;
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virtual size_t size() = 0;
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};
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//////////////////////////////////////////////////////////////////////////////
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// CKnapsackSolver //
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//////////////////////////////////////////////////////////////////////////////
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/// This class resolves the knapsack problem, in french "probleme du sac a
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/// dos"
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class CKnapsackSolver
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{
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public:
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enum Algorithm
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{
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UndefinedAlgorithm,
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Optimal,
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FullAddCheck,
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AddCheck,
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FastAddCheck,
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FullSingleReplace,
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SingleReplace,
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FastSingleReplace,
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VeryFastSingleReplace,
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//- /!\ Algorithms below don't respect constraints
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TakeAll
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};
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static std::string toString(Algorithm a);
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static CKnapsackSolver::Algorithm fromString(std::string const& a);
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private:
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IKnapsackContext* _Context;
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bool* _Take;
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bool _AllocatedTake;
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float _WBest;
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float _VBest;
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float _WMax;
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public:
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explicit CKnapsackSolver(IKnapsackContext* context, bool* take = NULL);
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virtual ~CKnapsackSolver();
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bool take(size_t i);
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float totalWeight();
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float totalValue();
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float totalFreeWeight();
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/// @param wMax Max weight that can be taken
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/// @note Not thread safe
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void optimize(float wMax, Algorithm algorithm = Optimal);
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private:
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float weight(size_t i);
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float value(size_t i);
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size_t size();
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/// @name Algorithms entry points
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//@{
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void optimizeOptimal();
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void optimizeFullAddCheck();
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void optimizeAddCheck();
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void optimizeFastAddCheck();
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void optimizeFullSingleReplace();
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void optimizeSingleReplace();
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void optimizeFastSingleReplace();
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void optimizeVeryFastSingleReplace();
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void optimizeTakeAll();
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//@}
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/// @name Algorithms helper functions
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//@{
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void optimizeOptimalRec(int i, float w, float v, bool* take);
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//@}
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};
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//////////////////////////////////////////////////////////////////////////////
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// CKnapsackContext //
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//////////////////////////////////////////////////////////////////////////////
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class CKnapsackContext
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: public IKnapsackContext
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{
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size_t _Size;
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float* _Weights;
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float* _Values;
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public:
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CKnapsackContext(size_t size, float* weights, float* values);
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virtual float weight(size_t i);
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virtual float value(size_t i);
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virtual size_t size();
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};
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#endif
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