Updated repo structure and added new files

Author: shreyasvedpathak

Linked List/linkedlist.py

@@ -0,0 +1,131 @@
+import os
+from typing import Sized
+
+class _Node:
+    __slots__ = '_element', '_link'
+
+    def __init__(self, element, link):
+        self._element = element
+        self._link = link
+
+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._link = newest
+
+        self._tail = newest
+        self._size += 1
+
+    def addFirst(self, e):
+
+        newest = _Node(e, None)
+
+        if self.isempty():
+            self._head = newest
+            self._tail = newest
+        else:
+            newest._link = self._head
+            self._head = newest
+        self._size += 1
+
+    def addAnywhere(self, e, index):
+
+        newest = _Node(e, None)
+
+        i = index - 1
+        p = self._head
+
+        if self.isempty():
+            self.addFirst(e)
+        else:
+            for i in range(i):
+                p = p._link
+            newest._link = p._link
+            p._link = newest
+        self._size += 1
+
+    def display(self):
+        if self.isempty() == 0:
+            p = self._head
+            while p:
+                print(p._element, end='-->')
+                p = p._link
+            print("NULL")
+        else:
+            print("List is Empty")
+
+    def search(self, key):
+        p = self._head
+        index = 0
+        while p:
+            if p._element == key:
+                return index
+            p = p._link
+            index += 1
+        return -1
+
+###############################################################################
+
+def options():
+    options_list = ['Add item', 'Add First', 'Add Anywhere', 'Display List', 'Print Size', 'Search', 'Exit']
+
+    print("MENU")
+    for i, option in enumerate(options_list):
+        print(f'{i + 1}. {option}')    
+
+    choice = int(input("Enter choice: "))
+    return choice
+
+def switch_case(choice):
+
+    os.system('cls')
+    if choice == 1:
+        elem = int(input("Enter Item: "))
+        L.addLast(elem)
+        print("Added Item at Last!\n\n")
+    elif choice == 2:
+        elem = int(input("Enter Item: "))
+        L.addFirst(elem)
+        print("Added Item at First!\n\n")
+    elif choice == 3:
+        elem = int(input("Enter Item: "))
+        index = int(input("Enter Index: "))
+        L.addAnywhere(elem, index)
+        print(f"Added Item at index {index}!\n\n")
+    elif choice == 4:
+        print("List: ", end='')
+        L.display()
+        print("\n")
+    elif choice == 5:
+        print("Size:", len(L))
+        print("\n")
+    elif choice == 6:
+        key = int(input("Enter item to search: "))
+        if L.search(key) >= 0:
+            print(f"Item {key} found at index position {L.search(key)}\n\n")
+        else:
+            print("Item not in the list\n\n")
+
+    elif choice == 7:
+        exit
+
+
+L = LinkedList()
+while True:
+    choice = options()
+    switch_case(choice)