Created DetectLoopInLinkedList.cpp

DetectLoopInLinkedList.cpp

@@ -0,0 +1,89 @@
+
+#include <bits/stdc++.h>
+using namespace std;
+
+struct Node {
+	int key;
+	struct Node* next;
+};
+
+Node* newNode(int key)
+{
+	Node* temp = new Node;
+	temp->key = key;
+	temp->next = NULL;
+	return temp;
+}
+
+void printList(Node* head)
+{
+	while (head != NULL) {
+		cout << head->key << " ";
+		head = head->next;
+	}
+	cout << endl;
+}
+
+int distance(Node* first, Node* last)
+{
+	int counter = 0;
+
+	Node* curr;
+	curr = first;
+
+	while (curr != last) {
+		counter += 1;
+		curr = curr->next;
+	}
+
+	return counter + 1;
+}
+
+bool detectLoop(Node* head)
+{
+
+	Node* temp = new Node;
+
+	Node *first, *last;
+
+	first = head;
+	last = head;
+
+	int current_length = 0;
+
+	int prev_length = -1;
+
+	while (current_length > prev_length && last != NULL) {
+
+		prev_length = current_length;
+
+		current_length = distance(first, last);
+
+		last = last->next;
+	}
+
+	if (last == NULL) {
+		return false;
+	}
+	else {
+		return true;
+	}
+}
+int main()
+{
+	Node* head = newNode(1);
+	head->next = newNode(2);
+	head->next->next = newNode(3);
+	head->next->next->next = newNode(4);
+	head->next->next->next->next = newNode(5);
+
+	head->next->next->next->next->next = head->next->next;
+
+	bool found = detectLoop(head);
+	if (found)
+		cout << "Loop Found";
+	else
+		cout << "No Loop Found";
+
+	return 0;
+}