From 1f19d921b0c6a82f2a178ba3effc92c847c943b3 Mon Sep 17 00:00:00 2001 From: Luke Manyamazi Date: Mon, 10 Nov 2025 09:50:33 +0200 Subject: [PATCH] added code for the linked list --- .gitignore | 2 +- Sprint-2/implement_linked_list/linked_list.py | 65 +++++++++++++++++++ 2 files changed, 66 insertions(+), 1 deletion(-) diff --git a/.gitignore b/.gitignore index bfb5886..e6a373a 100644 --- a/.gitignore +++ b/.gitignore @@ -1,4 +1,4 @@ .DS_Store node_modules -.venv +venv __pycache__ diff --git a/Sprint-2/implement_linked_list/linked_list.py b/Sprint-2/implement_linked_list/linked_list.py index e69de29..20f0870 100644 --- a/Sprint-2/implement_linked_list/linked_list.py +++ b/Sprint-2/implement_linked_list/linked_list.py @@ -0,0 +1,65 @@ +class LinkedList: + class Node: + def __init__(self, value): + self.value = value + self.next = None + self.previous = None + + def __init__(self): + self.head = None + self.tail = None + + def push_head(self, value): + """Add an element to the start of the list. Returns a handle to the node.""" + new_node = self.Node(value) + + if self.head is None: + # List is empty + self.head = new_node + self.tail = new_node + else: + # Add to front + new_node.next = self.head + self.head.previous = new_node + self.head = new_node + + return new_node + + def pop_tail(self): + """Remove and return the element from the end of the list.""" + if self.tail is None: + raise IndexError("pop from empty list") + + value = self.tail.value + + if self.head == self.tail: + # Only one element + self.head = None + self.tail = None + else: + # Multiple elements + self.tail = self.tail.previous + self.tail.next = None + + return value + + def remove(self, node): + """Remove a specific node from the list using the handle from push_head.""" + if node is None: + return + + if node.previous is not None: + node.previous.next = node.next + else: + # node is head + self.head = node.next + + if node.next is not None: + node.next.previous = node.previous + else: + # node is tail + self.tail = node.previous + + # Clean up references + node.next = None + node.previous = None \ No newline at end of file