Built Linked List functionality

Author: pythonioncoder

.idea/.gitignore

@@ -1,3 +1,135 @@
-class LinkedList():
-  def __init__(self):
-    pass
+class Node:
+    def __init__(self, value):
+        self.value = value
+        self.next = None
+
+
+class LinkedList:
+    def __init__(self, value):
+        new_node = Node(value)
+        self.head = new_node
+        self.tail = new_node
+        self.length = 1
+
+    def print_list(self):
+        temp = self.head
+        while temp is not None:
+            print(temp.value)
+            temp = temp.next
+
+    def append(self, value):
+        # appending is O(1) due to the simple changing of tail pointer
+        new_node = Node(value)
+        if self.head is None:
+            self.head = new_node
+            self.tail = new_node
+        else:
+            self.tail.next = new_node
+            self.tail = new_node
+        self.length += 1
+        return True
+
+    def pop(self):
+        # popping is O(n) because you need to iterate through the list to find the second to last value
+        if self.head is None:
+            return None
+        elif self.length == 1:
+            right = self.head
+            self.head = None
+            self.tail = None
+        else:
+            left, right = self.head, self.head.next
+            while right is not self.tail:
+                left = left.next
+                right = right.next
+            self.tail = left
+            self.tail.next = None
+        self.length -= 1
+        return right
+
+    def prepend(self, value):
+        # O(1)
+        new_node = Node(value)
+        new_node.next = self.head
+        self.head = new_node
+        if self.tail is None:
+            self.tail = new_node
+        self.length += 1
+        return True
+
+    def pop_first(self):
+        # O(1) since the second element is easily accessible
+        temp = self.head
+        if self.head is None:
+            return None
+        elif self.length == 1:
+            self.head = None
+            self.tail = None
+        else:
+            self.head = self.head.next
+        temp.next = None
+        self.length -= 1
+        return temp
+
+    def get(self, index):
+        # O(n)
+        if index < 0 or index >= self.length:
+            return None
+
+        current = self.head
+        for _ in range(index):
+            current = current.next
+        return current
+
+    def set_value(self, index, value):
+        node = self.get(index)
+        if node:
+            node.value = value
+            return True
+        return False
+
+    def insert(self, index, value):
+        # O(n) to iterate through the list
+        left = self.get(index-1)
+        if index == 0:
+            return self.prepend(value)
+        elif index == self.length:
+            return self.append(value)
+        elif left:
+            new_node = Node(value)
+            new_node.next = left.next
+            left.next = new_node
+            self.length += 1
+            return True
+        return False
+
+    def remove(self, index):
+        # O(n) to find item
+        if index == 0:
+            return self.pop_first()
+        elif index == self.length - 1:
+            return self.pop()
+        elif index < 0 or index >= self.length:
+            return None
+        left = self.get(index-1)
+        right = left.next
+        left.next = right.next
+        right.next = None
+        self.length -= 1
+        return True
+
+    def reverse(self):
+        if self.head is None:
+            return None
+        elif self.length == 1:
+            return True
+        temp = self.head
+        self.head = self.tail
+        self.tail = temp
+        right = temp.next
+        left = None
+        for _ in range(self.length):
+            right = temp.next
+            temp.next = left
+            left = temp
+            temp = right