algorithm: find the middle of linked-list

Data-Structures/Linked-List/MiddleOfLinkedList.js

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+/**
+ * A LinkedList based solution for Detect a Cycle in a list
+ * https://afteracademy.com/blog/middle-of-the-linked-list
+ */
+
+function main () {
+  /*
+    Problem Statement:
+    Given the head of a singly linked list, return the middle node of the linked list.
+    If there are two middle nodes, return the second middle node.
+
+    Note:
+    * While Solving the problem in given link below, don't use main() function.
+    * Just use only the code inside main() function.
+    * The purpose of using main() function here is to avoid global variables.
+
+    Link for the Problem: https://leetcode.com/problems/middle-of-the-linked-list/
+    */
+  const head = '' // Reference to head is given in the problem. So please ignore this line
+  let fast = head
+  let slow = head
+
+  if (head.next == null) { return head }
+
+  while (fast != null && fast.next != null) {
+    fast = fast.next.next
+    slow = slow.next
+  }
+  return slow
+}
+
+main()