How long of periods can cats be by themselves?

Me and my mother went on a roadtrip one day, so we had to leave my cat alone for about a week. we gave it ALOT OF FOOD AND WATER. and when i came to visit her on the 3rd day, there was ants crawling all around her food and she was hungry and stuff. i dont really think it will be good to leave the cat by itsself. you can have a friend check on it constantly. like twice a day to feed it and give it love