Floyd’s Cycle Finding Algorithm

cpp/Floyd’s Cycle Finding Algorithm

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+#include <bits/stdc++.h>
+using namespace std;
+
+class Node {
+public:
+    int data;
+    Node* next;
+
+    Node(int data)
+    {
+        this->data = data;
+        next = NULL;
+    }
+};
+
+Node* head = NULL;
+class Linkedlist {
+public:
+    void insert(int value)
+    {
+        Node* newNode = new Node(value);
+        if (head == NULL)
+            head = newNode;
+        else {
+            newNode->next = head;
+            head = newNode;
+        }
+    }
+
+    bool detectLoop()
+    {
+        Node *slowPointer = head,
+             *fastPointer = head;
+
+        while (slowPointer != NULL
+               && fastPointer != NULL
+               && fastPointer->next != NULL) {
+            slowPointer = slowPointer->next;
+            fastPointer = fastPointer->next->next;
+            if (slowPointer == fastPointer)
+                return 1;
+        }
+
+        return 0;
+    }
+};
+
+int main()
+{
+    Linkedlist l1;
+    // inserting new values
+    l1.insert(11);
+    l1.insert(22);
+    l1.insert(33);
+    l1.insert(44);
+    l1.insert(55);
+
+    Node* temp = head;
+    while (temp->next != NULL)
+        temp = temp->next;
+
+    temp->next = head;
+
+
+    if (l1.detectLoop())
+        cout << "Loop exists in the"
+             << " Linked List" << endl;
+    else
+        cout << "Loop does not exists "
+             << "in the Linked List" << endl;
+
+    return 0;
+}