ReverseLinked.java

package LeetcodePractice;
public class ReverseLinked {
    static class ListNode {
        int val;
        ListNode next;
        ListNode(int val) { this.val = val; }
    }

    public static ListNode reverseList(ListNode head) {
        ListNode prev = null;
        ListNode curr = head;
        while (curr != null) {
            ListNode next = curr.next; // Save next
            curr.next = prev;          // Reverse link
            prev = curr;               // Move prev forward
            curr = next;               // Move curr forward
        }
        return prev; // New head
    }

   
    public static ListNode createList(int[] values) {
        ListNode dummy = new ListNode(0);
        ListNode current = dummy;
        for (int val : values) {
            current.next = new ListNode(val);
            current = current.next;
        }
        return dummy.next;
    }


    public static void printList(ListNode head) {
        while (head != null) {
            System.out.print(head.val);
            if (head.next != null) System.out.print(" -> ");
            head = head.next;
        }
        System.out.println();
    }


    public static void main(String[] args) {
        int[] input = {1, 2, 3, 4, 5};  
        ListNode head = createList(input);

        System.out.print("Original List: ");
        printList(head);

        head = reverseList(head);

        System.out.print("Reversed List: ");
        printList(head);
    }
}