Linked List

Author: codehariom

linked list/LLAddFirstElement.py

@@ -0,0 +1,72 @@
+class _Node:
+    __slots__ = '_element', '_next'
+
+    def __init__(self, element, next):
+        self._element = element
+        self._next = next
+
+class LinkedList:
+    def __init__(self):
+        self._head = None
+        self._tail = None
+        self._size = 0
+
+    def __len__(self):
+        return self._size
+
+    def isempty(self):
+        return self._size == 0
+
+    def addlast(self, e):
+        newest = _Node(e, None)
+        if self.isempty():
+            self._head = newest
+        else:
+            self._tail._next = newest
+        self._tail = newest
+        self._size += 1
+
+    def display(self):
+        p = self._head
+        while p:
+            print(p._element,end='-->')
+            p = p._next
+        print()
+
+    def search(self,key):
+        p = self._head
+        index = 0
+        while p:
+            if p._element == key:
+                return index
+            p = p._next
+            index = index + 1
+        return -1
+
+    def addfirst(self, e):
+        newest = _Node(e, None)
+        if self.isempty():
+            self._head = newest
+            self._tail = newest
+        else:
+            newest._next = self._head
+            self._head = newest
+        self._size += 1
+
+L = LinkedList()
+L.addlast(7)
+L.addlast(4)
+L.addlast(12)
+L.addlast(8)
+L.addlast(3)
+L.display()
+print('Size:',len(L))
+L.addfirst(15)
+L.display()
+print('Size:',len(L))
+L.addfirst(25)
+L.display()
+print('Size:',len(L))
+L.addlast(35)
+L.display()
+print('Size:',len(L))