Floyd's_Cycle_Detection.py

class Node:
    def __init__(self, data): 
        self.data = data 
        self.next = None
  
class LinkedList: 
    # Function to initialize head 
    def __init__(self): 
        self.head = None
  
    # Function to insert node in Linked List
    def insert(self, val): 
        temp = Node(val) 
        temp.next = self.head 
        self.head = temp

    # Function to detect cycle in Linked List  
    def detectCycle(self): 
        slow_ptr = self.head 
        fast_ptr = self.head 
        while(fast_ptr and fast_ptr.next): 
            slow_ptr = slow_ptr.next
            fast_ptr = fast_ptr.next.next
            if slow_ptr == fast_ptr: 
                return True
        return False
  
# Driver Code
mylist = LinkedList()
values=[10, 20, 30, 40]
n= len(values)
for i in range(n-1,-1,-1):
    mylist.insert(values[i])
  
# Creating a loop in Linked List
mylist.head.next.next.next.next = mylist.head.next
if mylist.detectCycle():
    print("Cycle found")
else:
    print("No cycle found")