permutations.h

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/******************************************************************************
The MIT License(MIT)
 
Embedded Template Library.
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https://www.etlcpp.com
 
Copyright(c) 2018 John Wellbelove
 
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#ifndef ETL_PERMUTATIONS_INCLUDED
#define ETL_PERMUTATIONS_INCLUDED
 
#include "platform.h"

 
namespace etl
{
  //***************************************************************************
  //***************************************************************************
  template <size_t Value, size_t KV>
  struct permutations
  {
    static ETL_CONSTANT size_t value = Value * permutations<Value - 1, KV - 1>::value;
  };
 
  template <size_t Value, size_t KV>
  ETL_CONSTANT size_t permutations<Value, KV>::value;
 
  //***************************************************************************
  //***************************************************************************
  template <size_t Value>
  struct permutations<Value, 0>
  {
    static ETL_CONSTANT size_t value = 1UL;
  };
 
  template <size_t Value>
  ETL_CONSTANT size_t permutations<Value, 0>::value;
 
#if ETL_USING_CPP17
  template <size_t Value, size_t KV>
  inline constexpr size_t permutations_v = permutations<Value, KV>::value;
#endif
}
 
#endif