When I want to add an element at the end of my linked list it result in an infinite loop, here's the method i used
#insert at the end of the list
def append(self, data=None):
new_node = Node(data)
if self.head is None:
self.head = new_node
itr = self.head
while itr.next:
itr.next = new_node
itr = itr.next
Your code should return after adding the new node at the head if the list is empty.
After that your while loop is an infinite loop
You need to update it's position BEFORE you add to it and then add to it outside the loop
def append(self, data=None):
new_node = Node(data)
if self.head is None:
self.head = new_node
return
itr = self.head
while itr.next:
itr = itr.next
itr.next = new_node
Also your Node() should have a parameter for next
Your problem is in the loop:
while itr.next:
itr.next = new_node
itr = itr.next
When appending an item to an empty list, itr is initially is equal to new_node.
You set itr.next to new_node, so now new_node.next is equal to new_node. You have now created a cycle in your list, so it will loop forever.
When appending an item to your list, you should only be modifying the last element - the loop only serves to traverse the list to get to the end. It should look like:
def append(self, data=None):
new_node = Node(data)
if self.head is None:
self.head = new_node
else:
# you only need to traverse the list when it isn't empty
itr = self.head
while itr.next:
itr = itr.next
itr.next = new_node # only add the new node after traversing the list
That being said, this method of appending is O(n) complexity, and you can make it O(1) by keeping a pointer to the tail of the list and modifying the tail without traversing the list to find it.
