CodeYourFuture · TzeMingHo · Jun 17, 2026 · cjyuan · Jun 18, 2026
diff --git a/Sprint-2/implement_lru_cache/linked_list.py b/Sprint-2/implement_lru_cache/linked_list.py
@@ -0,0 +1,69 @@
+class Node:
+    def __init__(self, key, value):
+        self.key = key
+        self.value = value
+        self.previous = None
+        self.next = None
+
+class LinkedList:
+    def __init__(self):
+        self.head = None
+        self.tail = None
+
+    def push_head(self, new_node):
+        new_node.previous = None
+        new_node.next = None
+
+        if self.head == None:
+            self.head = new_node
+            self.tail = new_node
+        else:
+            new_node.next = self.head
+            self.head.previous = new_node
+            self.head = new_node
+
+        return new_node
+
+    def pop_tail(self):
+
+        if self.tail == None:
+            return None
+
+        return self.remove(self.tail)
+
+    def remove(self, node):
+        if self.head == None and self.tail == None:
+            return
+
+        new_previous = node.previous
+        new_next = node.next
+
+        if self.head == node and self.tail == node:
+            self.head = None
+            self.tail = None
+        elif self.head == node :
+            new_next.previous = None
+            self.head = new_next
+        elif self.tail == node:
+            new_previous.next = None
+            self.tail = new_previous
+        elif new_next and new_previous:
+            new_previous.next = new_next
+            new_next.previous = new_previous
+
+        node.previous = None
+        node.next = None
+        return node
+
+    def push_tail(self, new_node):
+        new_node.previous = None
+        new_node.next = None
+
+        if self.tail == None:
+            self.tail = new_node
+            self.head = new_node
+        else:
+            self.tail.next = new_node
+            new_node.previous = self.tail
+            self.tail = new_node
+        return new_node
diff --git a/Sprint-2/implement_lru_cache/lru_cache.py b/Sprint-2/implement_lru_cache/lru_cache.py
@@ -0,0 +1,29 @@
+from linked_list import LinkedList, Node
+
+class LruCache:
+    def __init__(self, limit):
+        if limit <= 0:
+            raise ValueError("limit must be positive")
+        self.limit = limit
+        self.dict = {}
+        self.linked_list = LinkedList()
+
+    def get(self, key):
+        if key not in self.dict:
+            return None
+        else:
+            most_recent_node = self.linked_list.remove(self.dict[key])
+            self.linked_list.push_head(most_recent_node)
+            return most_recent_node.value
+
+    def set(self, key, value):
+        if key in self.dict:
+            self.dict[key].value = value
+            self.get(key)
+        else:
+            if len(self.dict) == self.limit:
+                removed_node = self.linked_list.pop_tail()
+                del self.dict[removed_node.key]
+            self.dict[key] = Node(key, value)
+            self.linked_list.push_head(self.dict[key])
+