Exercise_3.py

#// Time Complexity : O(n)
#// Space Complexity : O(n) but each operation uses O(1) extra space
#// Did this code successfully run on Leetcode : Yes
#// Any problem you faced while coding this : No
# Node class  
class Node:  
  
    # Function to initialise the node object  
    def __init__(self, data):  
        self.data = data
        self.next = None
        
class LinkedList: 
  
    def __init__(self): 
        self.head = None
        
  
    def push(self, new_data): 
        new_node = Node(new_data)
        new_node.next = self.head
        self.head = new_node
        
  
    # Function to get the middle of  
    # the linked list 
    def printMiddle(self): 
        slow = self.head
        fast = self.head
        while fast is not None and fast.next is not None:
            slow = slow.next
            fast = fast.next.next
            
        if slow is not None:
            print("Middle element is:", slow.data)
        else:
            print("List is empty")

# Driver code 
list1 = LinkedList() 
list1.push(5) 
list1.push(4) 
list1.push(2) 
list1.push(3) 
list1.push(1) 
list1.printMiddle()