In "The Most Dangerous Game," how can the reader tell that Zaroff is smart?

In the story "The Most Dangerous Game", (which I recently
read in my English Class) you can tell that General Zaroff is smart, because he set up a
game, where since he is tired of hunting animals, because its too easy for him, he wants
to hunt people, so he sets up Sanger Rainsford in the woods with a survival knife,
etc..and plans to hunt him--and eventually kill
him.

Rainsford can certaintly tell that General Zaroff is
intelligent from the way that he explains his mastermind plot to him. Rainsford could
tell he most likely was pretty smart also because he greets him by getting the servant
Ivan away, because he intimitated Rainsford, which Zaroff was smart enough to realize,
and was wearing clothing as if he was wealthy, in his big mansion, and very
affable--enough to automaticly shake his hand. So right off the bat, Rainsford most
likely was thinking "This guy is very smart and
affable".

It is very obvious that General Zaroff shows
intelligence thoughout "The Most Dangerous Game". Although in the end, he was not smart
enough to win the game. Sanger Rainsford ended up winning, by outsmarting Zaroff. He
jumped off the cliff, swum around the island, into Zarroffs bedroom, hid, and surprised
him, and got to sleep in Zaroffs bed, while the General was killed. Rainsford thought he
had never slept better.