linked-list-cycle solution

Author: krokerdile

linked-list-cycle/krokerdile.js

@@ -0,0 +1,23 @@
+/**
+ * Definition for singly-linked list.
+ * function ListNode(val) {
+ *     this.val = val;
+ *     this.next = null;
+ * }
+ */
+
+/**
+ * @param {ListNode} head
+ * @return {boolean}
+ */
+var hasCycle = function(head) {
+    let list = new Set();
+    while (head != null) {
+        if (list.has(head))
+            return true;
+        list.add(head);
+        head = head.next;
+    }
+
+    return false;
+};