Write a function that takes an array of numbers a, and
returns an array with the elements of a in reversed
order. Use only Array#length and array indices for
array access. (In other words, no Array#reverse,
Array#<<, Array#pop, etc!)
Reverse the array in O(1) (constant) space, that is, don't
use more than a fixed number of additional variables,
regardless of the length of a.
Write a list_append function, that takes a linked
list l1 and a linked list l2 and returns a
linked list with l2 appended to the end of l1.
(Think l1 + l2).
Write a list_prepend function, that takes a linked
list l1 and a linked list l2 and returns a
linked list with l2 prepended to the beginning of l1.
(Think l2 + l1).
Write a method insert_after that takes a linked list
l1, a linked list l2, and a value v, and
inserts the list l2 after the first occurance of
the value v in l1.
Write a method insert_before that takes a linked list
l1, a linked list l2, and a value v, and
inserts the list l2 before the first occurance of
the value v in l1.