Added Floyd's Cycle Detect Algorithm

C++/floyd_cycle_detection_algo.cpp

@@ -0,0 +1,46 @@
+#include <iostream>
+#include <bits/stdc++.h>
+
+using namespace std;
+
+struct Node{
+    Node *next;
+    int val;
+    Node(int v){
+        val = v;
+        next = NULL;
+    }
+};
+
+bool cycleDetect(Node *head){
+    Node* slow = head;
+    Node* fast = head;
+    while(fast && fast->next){
+        slow = slow->next;
+        fast = fast->next->next;
+        if(slow == fast) break;
+    }
+
+    if(fast != slow) return false;
+    slow = head;
+    while(slow != fast){
+        slow = slow->next;
+        fast = fast->next;
+    }
+
+    cout<<"The node where cycle starts is "<<slow->val<<"\n";
+    return true;
+}
+
+
+int main(){
+    Node* head = new Node(0);
+    head->next = new Node(1);
+    head->next->next = new Node(2);
+    head->next->next->next = new Node(3);
+    head->next->next->next->next = head->next;
+    if(!cycleDetect(head)){
+        cout<<"No cycle detected"<<"\n";
+    }
+    return 0;
+}