Function symmetricArray

sample/symmetric.cpp:19–29

}

constexpr bool symmetricArray(std::array<int32_t, 5> const &arr)
{
  using namespace matchit;
  Id<int32_t> i, j;
  return match(arr)(
      // clang-format off
         pattern | ds(i, j, _, j, i) = expr(true),
         pattern | _                 = expr(false)
      // clang-format on
  );
}

static_assert(symmetricArray(std::array<int32_t, 5>{5, 0, 3, 7, 10}) == false);
static_assert(symmetricArray(std::array<int32_t, 5>{5, 0, 3, 0, 5}) == true);