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#ifndef RANDOM_HPP
#define RANDOM_HPP
# include "random.t.hpp"
# include "sanity.hpp"
# include <random>
// This is not namespace random since that collides with a C function,
// but this can be revisited when everything goes into namespace tmwa.
namespace random_
{
/// Get a random number from 0 .. 2**32 - 1
extern std::mt19937 generate;
/// Get a random number from 0 .. bound - 1
inline
int to(int bound)
{
std::uniform_int_distribution<int> dist(0, bound - 1);
return dist(generate);
}
/// Get a random number from low .. high (inclusive!)
inline
int in(int low, int high)
{
std::uniform_int_distribution<int> dist(low, high);
return dist(generate);
}
inline
bool coin()
{
// sigh, can't specify <bool> directly ...
std::uniform_int_distribution<int> dist(false, true);
return dist(generate);
}
inline
bool chance(Fraction f)
{
if (f.num <= 0)
return false;
if (f.num >= f.den)
return true;
return random_::to(f.den) < f.num;
}
// C is usually one of:
// std::vector<T>
// std::initializer_list<T>
// std::array<T, n>
template<class C>
auto choice(C&& c) -> decltype(*c.begin())
{
return *(c.begin() + random_::to(c.size()));
}
// allow bare braces
template<class T>
T choice(std::initializer_list<T>&& il)
{
return random_::choice(il);
}
} // namespace random_
#endif // RANDOM_HPP
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