Delete_node_in_DLL.java

// { Driver Code Starts
//Initial Template for Java
import java.util.*;

class Node {
  int data;
  Node next;
  Node prev;

  Node(int d) {
    data = d;
    next = prev = null;
  }
}

class Delete_Node_From_DLL {
  Node head;
  Node tail;

  void addToTheLast(Node node) {
    if (head == null) {
      head = node;
      tail = node;
    } else {
      tail.next = node;
      tail.next.prev = tail;
      tail = tail.next;
    }
  }

  void printList(Node head) {
    Node temp = head;
    while (temp != null) {
      System.out.print(temp.data + " ");
      temp = temp.next;
    }
    System.out.println();
  }

  public static void main(String args[]) {
    Scanner sc = new Scanner(System.in);
    int t = sc.nextInt();
    while (t > 0) {
      int n = sc.nextInt();
      Delete_Node_From_DLL list = new Delete_Node_From_DLL();

      int a1 = sc.nextInt();
      Node head = new Node(a1);
      list.addToTheLast(head);

      for (int i = 1; i < n; i++) {
        int a = sc.nextInt();
        list.addToTheLast(new Node(a));
      }
      a1 = sc.nextInt();
      Solution g = new Solution();
      // System.out.println(list.temp.data);
      Node ptr = g.deleteNode(list.head, a1);
      list.printList(ptr);
      t--;
    }
  }
}

class Solution {
  Node deleteNode(Node head, int x) {
    if (head == null)
      return null;

    if (head.next == null && x == 1)
      return null;

    if (x == 1) {
      head = head.next;
      head.prev = null;
      return head;
    }

    Node curr = head;
    int count = 2;
    while (count <= x) {
      curr = curr.next;
      count++;
    }
    if (curr.next == null) {
      curr.prev.next = null;
    } else {
      curr.prev.next = curr.next;
      curr.next.prev = curr.prev;
    }

    return head;
  }
}