feat: 141. Linked List Cycle

Author: gwbaik9717

linked-list-cycle/gwbaik9717.js

@@ -0,0 +1,22 @@
+// Time complexity: O(n)
+// Space complexity: O(1)
+
+/**
+ * @param {ListNode} head
+ * @return {boolean}
+ */
+var hasCycle = function (head) {
+  let turtle = head;
+  let rabbit = head;
+
+  while (turtle && rabbit && rabbit.next) {
+    turtle = turtle.next;
+    rabbit = rabbit.next.next;
+
+    if (turtle === rabbit) {
+      return true;
+    }
+  }
+
+  return false;
+};