When it is required to find the common element that occurs for the first time between two linked lists, a method to add elements to the linked list, and a method to get the common element that occurs for the first time in these linked lists is defined.
Below is a demonstration for the same −
Example
class Node:
def __init__(self, data):
self.data = data
self.next = None
class LinkedList_structure:
def __init__(self):
self.head = None
self.last_node = None
def add_vals(self, data):
if self.last_node is None:
self.head = Node(data)
self.last_node = self.head
else:
self.last_node.next = Node(data)
self.last_node = self.last_node.next
def first_common_val(list_1, list_2):
curr_1 = list_1.head
while curr_1:
data = curr_1.data
curr_2 = list_2.head
while curr_2:
if data == curr_2.data:
return data
curr_2 = curr_2.next
curr_1 = curr_1.next
return None
my_list_1 = LinkedList_structure()
my_list_2 = LinkedList_structure()
my_list = input('Enter the elements of the first linked list : ').split()
for elem in my_list:
my_list_1.add_vals(int(elem))
my_list = input('Enter the elements of the second linked list : ').split()
for elem in my_list:
my_list_2.add_vals(int(elem))
common_vals = first_common_val(my_list_1, my_list_2)
if common_vals:
print('The element that is present first in the first linked list and is common to both is {}.'.format(common))
else:
print('The two lists have no common elements')Output
Enter the elements of the first linked list : 45 67 89 123 45 Enter the elements of the second linked list : 34 56 78 99 0 11 The two lists have no common elements
Explanation
The ‘Node’ class is created.
Another ‘LinkedList_structure’ class with required attributes is created.
It has an ‘init’ function that is used to initialize the first element, i.e the ‘head’ to ‘None’.
A method named ‘add_vals’ is defined, that helps add a value to the stack.
Another method named ‘first_common_val’ is defined, that helps find the first common value that was found in the two linked lists.
Two instances of the ‘LinkedList_structure’ are created.
Elements are added to both the linked lists.
The ‘first_common_value’ method is called on these linked lists.
The output is displayed on the console.