How linked list used in car parking?

Answer 1

It isn't. In car parking the only thing we need to keep track of is tickets. When we issue a new ticket we place it at the end of the array. When we extract a (paid) ticket, we simply move the last ticket into its place. This allows constant-time insertion and extraction. The only cost is that we must perform a linear search in order to locate a ticket for extraction, but we can perform linear searches across an array much quicker than we can with a linked-list because we don't have the additional cost of dereferencing individual nodes. Note that even if the list were in sorted order, we cannot use a binary search because lists do not allow constant-time random access. Arrays do allow efficient binary searches but we must maintain sorted order to do so and that may well cost more than a simple linear search. Given that linear search must be performed regardless of which container we use, an array is the better choice of the two.