Merge pull request #2574 from robinyoon-dev/main

[robinyoon-dev] Week 09 Solutions

Author: SamTheKorean

linked-list-cycle/robinyoon-dev.js

@@ -0,0 +1,47 @@
+/**
+ * Definition for singly-linked list.
+ * function ListNode(val) {
+ *     this.val = val;
+ *     this.next = null;
+ * }
+ */
+
+/**
+ * @param {ListNode} head
+ * @return {boolean}
+ */
+var hasCycle = function (head) {
+
+    const visited = new Set();
+    let result = false;
+
+    while (head) {
+
+        let next = head.next;
+
+        if (next == null) {
+            result = false;
+            break;
+        }
+
+        let isExist = findElementInDp(head);
+
+        if (!isExist) {
+            visited.add(head);
+            head = next;
+        } else {
+            result = true;
+            break;
+        }
+    }
+
+    return result;
+
+    function findElementInDp(head) {
+        if (visited.has(head)) {
+            return true;
+        } else {
+            return false;
+        }
+    }
+};