Merge pull request TheAlgorithms#409 from pomkarnath98/cycle-detection-in-linkedlist

AnupKumarPanwar · web-flow · commit 868a401f8f87 · 2020-10-06T11:23:17.000+05:30
Cycle detection in linkedlist
diff --git a/Data-Structures/Linked-List/CycleDetection.js b/Data-Structures/Linked-List/CycleDetection.js
@@ -0,0 +1,32 @@
+/**
+ * A LinkedList based solution for Detect a Cycle in a list
+ * https://en.wikipedia.org/wiki/Cycle_detection
+ */
+
+function main () {
+  /*
+  Problem Statement:
+  Given head, the head of a linked list, determine if the linked list has a cycle in it.
+
+  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 aviod global variables.
+
+  Link for the Problem: https://leetcode.com/problems/linked-list-cycle/
+  */
+  const head = '' // Reference to head is given in the problem. So please ignore this line
+  let fast = head
+  let slow = head
+
+  while (fast != null && fast.next != null && slow != null) {
+    fast = fast.next.next
+    slow = slow.next
+    if (fast === slow) {
+      return true
+    }
+  }
+  return false
+}
+
+main()
