Added new Algorithm to find middle element of Linked List (#1822)

* Added new Algorithm to find middle element of Linked List

* Rename MiddleElementOfLinkedList.py to middle_element_of_linked_list.py

* changed "middle_element_of_linked_list.py" algorithm for taking input

* Update middle_element_of_linked_list.py

* Update middle_element_of_linked_list.py

* Update middle_element_of_linked_list.py

* Update middle_element_of_linked_list.py

* Update middle_element_of_linked_list.py

* Update middle_element_of_linked_list.py

* Update middle_element_of_linked_list.py

* Update middle_element_of_linked_list.py

* Update middle_element_of_linked_list.py

* Whack the trailing whitespace

Co-authored-by: Christian Clauss <cclauss@me.com>

data_structures/linked_list/middle_element_of_linked_list.py

@@ -0,0 +1,64 @@
+class Node:
+    def __init__(self, data: int) -> int:
+        self.data = data
+        self.next = None
+
+
+class LinkedList:
+    def __init__(self):
+        self.head = None
+
+    def push(self, new_data:int) -> int:
+        new_node = Node(new_data) 
+        new_node.next = self.head 
+        self.head = new_node
+        return self.head.data
+
+    def middle_element(self) -> int:
+        '''
+        >>> link = LinkedList()
+        >>> link.middle_element()
+        No element found.
+        >>> link.push(5)
+        5
+        >>> link.push(6)
+        6
+        >>> link.push(8)
+        8
+        >>> link.push(8)
+        8
+        >>> link.push(10)
+        10
+        >>> link.push(12)
+        12
+        >>> link.push(17)
+        17
+        >>> link.push(7)
+        7
+        >>> link.push(3)
+        3
+        >>> link.push(20)
+        20
+        >>> link.push(-20)
+        -20
+        >>> link.middle_element()
+        12
+        >>> 
+        '''
+        slow_pointer = self.head
+        fast_pointer = self.head
+        if self.head: 
+            while fast_pointer and fast_pointer.next: 
+                fast_pointer = fast_pointer.next.next
+                slow_pointer = slow_pointer.next
+            return slow_pointer.data
+        else:
+            print("No element found.")
+
+
+if __name__ == "__main__":
+    link = LinkedList()
+    for i in range(int(input().strip())):
+        data = int(input().strip())
+        link.push(data)
+    print(link.middle_element())