♻️ Day 27

Author: AkashRajpurohit

README.md

@@ -42,6 +42,7 @@
 3. [Bag of Tokens](https://leetcode.com/explore/challenge/card/october-leetcoding-challenge/562/week-4-october-22nd-october-28th/3506/) ➡️ [CPP Solution](Week4/bagOfTokensScore.cpp)
 4. [Stone Game IV](https://leetcode.com/explore/challenge/card/october-leetcoding-challenge/562/week-4-october-22nd-october-28th/3507/) ➡️ [CPP Solution](Week4/winnerSquareGame.cpp)
 5. [Champagne Tower](https://leetcode.com/explore/challenge/card/october-leetcoding-challenge/562/week-4-october-22nd-october-28th/3508/) ➡️ [CPP Solution](Week4/champagneTower.cpp)
+6. [Linked List Cycle II](https://leetcode.com/explore/challenge/card/october-leetcoding-challenge/562/week-4-october-22nd-october-28th/3509/) ➡️ [CPP Solution](Week4/detectCycle.cpp)
 
 ## Week 5 🚧
 

Week4/detectCycle.cpp

@@ -0,0 +1,33 @@
+/**
+ * Definition for singly-linked list.
+ * struct ListNode {
+ *     int val;
+ *     ListNode *next;
+ *     ListNode(int x) : val(x), next(NULL) {}
+ * };
+ */
+class Solution {
+public:
+    ListNode *detectCycle(ListNode *head) {
+        if(head == NULL) return NULL;
+        
+        ListNode* slow = head;
+        ListNode* fast = head;
+        
+        while(fast != NULL && fast->next != NULL) {
+            slow = slow->next;
+            fast = fast->next->next;
+            
+            if(slow == fast) {
+                slow = head;
+                while(slow != fast) {
+                    slow = slow->next;
+                    fast = fast->next;
+                }
+                return slow;
+            }
+        }
+        
+        return NULL;
+    }
+};