factorial.h

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 * Copyright 2017 The Apollo Authors. All Rights Reserved.
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 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
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 * http://www.apache.org/licenses/LICENSE-2.0
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#pragma once

#include <cstdint>

namespace apollo {
namespace common {
namespace math {

template <uint64_t N>
struct Factorial {
  enum { value = N * Factorial<N - 1>::value };
};

template <>
struct Factorial<0> {
  enum { value = 1 };
};

}  // namespace math
}  // namespace common
}  // namespace apollo