linked_list_utils.py

class Node:
    val: int
    next = None

    def __init__(self, val, next_node=None):
        self.val = val
        self. next = next_node

    def __str__(self):
        return f"({self.val}) -> {self.next}"


def link_list_of_list(arr) -> Node:
    head = Node(arr[0])
    now_elem = head
    for x in arr[1:]:
        now_elem.next = Node(x)
        now_elem = now_elem.next
    return head


def llol(arr):
    """Shorthand for (make) linked-list of list
    """
    return link_list_of_list(arr)


def lllen(head: Node) -> int:
    return len_of_ll(head)


def len_of_ll(head: Node) -> int:
    count = 0
    elem_now = head
    while elem_now:
        count += 1
        elem_now = elem_now.next

    return count


if __name__ == "__main__":
    ex1 = [1, 2, 3]
    print(link_list_of_list(ex1))