Final answer:
To insert an element into a list just before the rightmost item greater than it, you can use the given code. Examples are provided to illustrate the function's usage.
Step-by-step explanation:
To insert an element into a list just before the rightmost item greater than it, you can use the following code:
def insert(lst: list[int], v: int) -> None:
for i in range(len(lst)-1, -1, -1):
if lst[i] > v:
lst.insert(i, v)
return
lst.insert(0, v)
For example, if lst = [3, 10, 4, 2] and v = 5, calling insert(lst, v) will result in lst = [3, 5, 10, 4, 2]. Similarly, if lst = [5, 4, 2, 10] and v = 20, calling insert(lst, v) will result in lst = [20, 5, 4, 2, 10].