75 lines
2.5 KiB
C
75 lines
2.5 KiB
C
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///\file
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/******************************************************************************
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The MIT License(MIT)
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Embedded Template Library.
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https://github.com/ETLCPP/etl
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https://www.etlcpp.com
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Copyright(c) 2018 John Wellbelove
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Permission is hereby granted, free of charge, to any person obtaining a copy
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of this software and associated documentation files(the "Software"), to deal
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in the Software without restriction, including without limitation the rights
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to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
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copies of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions :
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The above copyright notice and this permission notice shall be included in all
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copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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SOFTWARE.
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******************************************************************************/
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#ifndef ETL_PERMUTATIONS_INCLUDED
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#define ETL_PERMUTATIONS_INCLUDED
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#include "platform.h"
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///\defgroup permutations permutations
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/// permutations<N, K> : Calculates K permutations from N.
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///\ingroup maths
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namespace etl
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{
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//***************************************************************************
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///\ingroup permutations
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/// Calculates permutations.
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//***************************************************************************
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template <size_t NV, size_t KV>
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struct permutations
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{
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static ETL_CONSTANT size_t value = NV * permutations<NV - 1, KV - 1>::value;
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};
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template <size_t NV, size_t KV>
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ETL_CONSTANT size_t permutations<NV, KV>::value;
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//***************************************************************************
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/// Calculates permutations.
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/// Specialisation for KV == 0.
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//***************************************************************************
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template <size_t NV>
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struct permutations<NV, 0>
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{
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static ETL_CONSTANT size_t value = 1UL;
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};
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template <size_t NV>
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ETL_CONSTANT size_t permutations<NV, 0>::value;
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#if ETL_USING_CPP17
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template <size_t NV, size_t KV>
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inline constexpr size_t permutations_v = permutations<NV, KV>::value;
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#endif
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}
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#endif
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