leetcode

commit 95babb3b94d468893fd6f56f96757bb15668b9d4
parent 8622b6f7ec0f1cccb93968b920d12221bea8afa8
Author: AndrewLockVI <andrewlaack1@gmail.com>
Date:   Tue, 25 Apr 2023 11:58:13 -0500

Completed linked list cycle problem with js

Diffstat:
A
linked-list-cycle/linked-list-cycle.js
 | 
35
+++++++++++++++++++++++++++++++++++

1 file changed, 35 insertions(+), 0 deletions(-)
diff --git a/linked-list-cycle/linked-list-cycle.js b/linked-list-cycle/linked-list-cycle.js
@@ -0,0 +1,35 @@
+//Find if a linked list contains a refrence to another node in the list.
+//This would create a circular refrence thus it would have no end.
+//To find this I created a set and then for each node checked to see
+//if it existed in the set. If it does exist in the set then the list is
+//circular because that would mean a refrence to another node is used multiple times
+//in the list. The time complexity of this is O(n) because I used a set which
+//has constant time searching.
+//Time: 71ms Beats: 69.27%
+//Memory: 46.3MB Beats: 5.82%
+
+/**
+ * Definition for singly-linked list.
+ * function ListNode(val) {
+ *     this.val = val;
+ *     this.next = null;
+ * }
+ */
+
+/**
+ * @param {ListNode} head
+ * @return {boolean}
+ */
+var hasCycle = function(head) {
+    let node_map = new Set();
+    while(head != null){
+        if(node_map.has(head)){
+            return true;
+        }
+        else{
+            node_map.add(head);
+        }
+        head = head.next;
+    }
+    return false;
+};