From e0991e08c12869e71bcdde512ed11c29d8d74624 Mon Sep 17 00:00:00 2001
From: Hriday-A <hriday.agarwal20103@gmail.com>
Date: Mon, 4 May 2026 15:46:22 -0500
Subject: [PATCH] Linked-List-1

---
 LL_cycle_II.java     | 25 +++++++++++++++++++++++++
 remove_nth_node.java | 25 +++++++++++++++++++++++++
 reverse_ll.java      | 18 ++++++++++++++++++
 3 files changed, 68 insertions(+)
 create mode 100644 LL_cycle_II.java
 create mode 100644 remove_nth_node.java
 create mode 100644 reverse_ll.java

diff --git a/LL_cycle_II.java b/LL_cycle_II.java
new file mode 100644
index 00000000..72700255
--- /dev/null
+++ b/LL_cycle_II.java
@@ -0,0 +1,25 @@
+// Time Complexity : O(n)
+// Space Complexity : O(1)
+// Did this code successfully run on Leetcode : yes
+public class LL_cycle_II {
+    public ListNode detectCycle(ListNode head) {
+        ListNode slow = head;
+        ListNode fast = head;
+        boolean flag = false;
+        while(fast!=null && fast.next!=null){
+            slow = slow.next;
+            fast=fast.next.next;
+            if(slow==fast){
+                flag = true;
+                break;
+            } 
+        }
+        fast = head; 
+        if(!flag) return null;
+        while(slow!=fast){
+            slow=slow.next;
+            fast=fast.next;
+        }
+        return slow;
+    }
+}
diff --git a/remove_nth_node.java b/remove_nth_node.java
new file mode 100644
index 00000000..b64175b7
--- /dev/null
+++ b/remove_nth_node.java
@@ -0,0 +1,25 @@
+// Time Complexity : O(n)
+// Space Complexity : O(1)
+// Did this code successfully run on Leetcode :yes 
+class Solution {
+    public ListNode removeNthFromEnd(ListNode head, int n) {
+        ListNode dummy = new ListNode(-1);
+        dummy.next = head;
+        ListNode slow= dummy;
+        ListNode fast = dummy;
+        int cnt=0;
+        while(cnt<=n){
+            fast = fast.next;
+            cnt++;
+        }
+        while(fast!=null){
+            slow=slow.next;
+            fast=fast.next;
+        }
+        ListNode temp = slow.next;
+        slow.next = slow.next.next;
+        temp.next = null;
+        return dummy.next; // head is no longer the orginal head if it was deleted
+
+    }
+}
\ No newline at end of file
diff --git a/reverse_ll.java b/reverse_ll.java
new file mode 100644
index 00000000..1802a987
--- /dev/null
+++ b/reverse_ll.java
@@ -0,0 +1,18 @@
+// Time Complexity : O(n)
+// Space Complexity :O(1)
+// Did this code successfully run on Leetcode : yes 
+// we use 3 pointers to reverse the list by storing the values with which we loose connection 
+class Solution {
+    public ListNode reverseList(ListNode head) {
+        ListNode curr = head;
+        ListNode prev = null;
+        while( curr!= null){
+            ListNode temp = curr.next;
+            curr.next = prev;
+            prev = curr;
+            curr = temp;
+            // System.out.println(curr);
+        }
+        return prev;
+    }
+}
\ No newline at end of file