def find_sum_reverse(n_1: Node, n_2: Node):
diff = get_size(n_1) - get_size(n_2)
for i in range(abs(diff)):
if diff < 0:
n_1 = add_leading_zero(n_1)
else:
n_2 = add_leading_zero(n_2)
n, carryover = find_sum_r(n_1, n_2)
if carryover > 0:
n_result = Node(carryover)
n_result.tail = n
return n_result
return n
def find_sum_r(n_1: Node, n_2: Node):
d_1 = n_1.data
d_2 = n_2.data
if not n_1.tail or not n_2.tail:
total = d_1 + d_2
result = total % 10
carryover = total // 10
return Node(result), carryover
n, carryover = find_sum_r(n_1.tail, n_2.tail)
total = d_1 + d_2 + carryover
result = total % 10
carryover = total // 10
n_result = Node(result)
n_result.tail = n
return n_result, carryover
def add_leading_zero(n: Node):
n_zero = Node(0)
n_zero.tail = n
return n_zero
def test_get_first_in_loop(self):
first_node_in_loop = Node('C')
linked_list = Node('A', Node('B', first_node_in_loop))
first_node_in_loop.tail = Node('D', Node('E', first_node_in_loop))
self.assertEqual(first_node_in_loop.data,
get_first_in_loop(linked_list).data)
