From fec6d266070bd93289af31ed7d05f721760fa1c8 Mon Sep 17 00:00:00 2001
From: shubh_goel2002 <80595515+vader22a@users.noreply.github.com>
Date: Sat, 15 Oct 2022 22:31:40 +0530
Subject: [PATCH] Create LOOP DETECTION.py

Language=Python
Loop Detection for Linklist.

Complexity Analysis:
Time complexity: O(n).
Only one traversal of the loop is needed.
Auxiliary Space: O(n).
n is the space required to store the value in hashmap.
---
 LOOP DETECTION.py | 66 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 66 insertions(+)
 create mode 100644 LOOP DETECTION.py

diff --git a/LOOP DETECTION.py b/LOOP DETECTION.py
new file mode 100644
index 0000000..9e76835
--- /dev/null
+++ b/LOOP DETECTION.py	
@@ -0,0 +1,66 @@
+class Node:
+ 
+    # Constructor to initialize
+    # the node object
+    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 a new
+    # node at the beginning
+    def push(self, new_data):
+        new_node = Node(new_data)
+        new_node.next = self.head
+        self.head = new_node
+ 
+    # Utility function to print it
+    # the linked LinkedList
+    def printList(self):
+        temp = self.head
+        while(temp):
+            print(temp.data, end=" ")
+            temp = temp.next
+ 
+    def detectLoop(self):
+        s = set()
+        temp = self.head
+        while (temp):
+ 
+            # If we already have
+            # this node in hashmap it
+            # means there is a cycle
+            # (Because we are encountering
+            # the node second time).
+            if (temp in s):
+                return True
+ 
+            # If we are seeing the node for
+            # the first time, insert it in hash
+            s.add(temp)
+ 
+            temp = temp.next
+ 
+        return False
+ 
+ 
+# Driver program for testing
+llist = LinkedList()
+llist.push(20)
+llist.push(4)
+llist.push(15)
+llist.push(10)
+ 
+# Create a loop for testing
+llist.head.next.next.next.next = llist.head
+ 
+if(llist.detectLoop()):
+    print("Loop found")
+else:
+    print("No Loop ")