4.6. Exercise: Arimu and Hats

Our friend Arimu loves hats and wants to buy as many hats as possible. Unfortunately, he can’t always afford all the hats in the store. So he needs to spend his money wisely, to be able to purchase the maximum number of hats.

Write a function named buy_hats which takes a list of integers as the costs of hats and an integer as Arimu’s money. This function finds the maximum number of hats Arimu can buy and returns it as an integer.

Hint: You might want to rearrange the list of hats in the increasing order of their prices.

Sample I/O:

>>> buy_hats([12, 3, 7, 5, 4, 8], 12)
3

>>> buy_hats([4, 3, 6, 2, 5, 5], 27)
6