141. Linked List Cycle

141. Linked List Cycle

Author: SteffiKeranJ

hasCycle.cpp

@@ -0,0 +1,17 @@
+// uses slow and fast pointer
+// if there is a cycle, the slow and fast pointer will meet at some point of time and we return true
+// else, the while loop will break at the end of the dead end of the list and we return false
+class Solution {
+public:
+    bool hasCycle(ListNode *head) {
+        if(!head) return false;
+        ListNode* slow =  head;
+        ListNode* fast = head;
+        while(fast->next && fast->next->next){
+            slow = slow->next;
+            fast = fast->next->next;
+            if(slow == fast) return true;
+        }
+        return false;
+    }
+};