# Java Arraylist

### Problem Statement :

```Sometimes it's better to use dynamic size arrays. Java's Arraylist can provide you this feature. Try to solve this problem using Arraylist.

You are given n lines. In each line there are zero or more integers. You need to answer a few queries where you need to tell the number located in yth position of xth line.

Input Format

The first line has an integer n. In each of the next n lines there will be an integer d denoting number of integers on that line and then there will be d space-separated integers. In the next line there will be an integer q denoting number of queries. Each query will consist of two integers x and y.

Constraints

1<=n<=20000
0<=d<=50000
1<=q<=1000
1<=x<=n
Each number will fit in signed integer.
Total number of integers in n lines will not cross 10^5.

Output Format

In each line, output the number located in yth position of xth line. If there is no such position, just print "ERROR!"```

### Solution :

```                            ```Solution in C :

import java.io.*;
import java.util.*;

public class Solution {

public static void main(String[] args)
{

Scanner scan = new Scanner(System.in);
ArrayList[] list= new ArrayList[20002];
int n;
n=scan.nextInt();
for(int i=1;i<=n;i++)
{

list[i]=new ArrayList();
int x=scan.nextInt();

for(int j=1;j<=x;j++)
{
int val=scan.nextInt();

}
}
int q=scan.nextInt();

for(int i=1;i<=q;i++)
{
int x,y;
x=scan.nextInt();
y=scan.nextInt();
try
{
System.out.println(list[x].get(y-1));
}catch(Exception e)
{
System.out.println("ERROR!");
}
}
}
}```
```

## Print the Elements of a Linked List

This is an to practice traversing a linked list. Given a pointer to the head node of a linked list, print each node's data element, one per line. If the head pointer is null (indicating the list is empty), there is nothing to print. Function Description: Complete the printLinkedList function in the editor below. printLinkedList has the following parameter(s): 1.SinglyLinkedListNode

## Insert a Node at the Tail of a Linked List

You are given the pointer to the head node of a linked list and an integer to add to the list. Create a new node with the given integer. Insert this node at the tail of the linked list and return the head node of the linked list formed after inserting this new node. The given head pointer may be null, meaning that the initial list is empty. Input Format: You have to complete the SinglyLink

Given a pointer to the head of a linked list, insert a new node before the head. The next value in the new node should point to head and the data value should be replaced with a given value. Return a reference to the new head of the list. The head pointer given may be null meaning that the initial list is empty. Function Description: Complete the function insertNodeAtHead in the editor below

## Insert a node at a specific position in a linked list

Given the pointer to the head node of a linked list and an integer to insert at a certain position, create a new node with the given integer as its data attribute, insert this node at the desired position and return the head node. A position of 0 indicates head, a position of 1 indicates one node away from the head and so on. The head pointer given may be null meaning that the initial list is e

## Delete a Node

Delete the node at a given position in a linked list and return a reference to the head node. The head is at position 0. The list may be empty after you delete the node. In that case, return a null value. Example: list=0->1->2->3 position=2 After removing the node at position 2, list'= 0->1->-3. Function Description: Complete the deleteNode function in the editor below. deleteNo

## Print in Reverse

Given a pointer to the head of a singly-linked list, print each data value from the reversed list. If the given list is empty, do not print anything. Example head* refers to the linked list with data values 1->2->3->Null Print the following: 3 2 1 Function Description: Complete the reversePrint function in the editor below. reversePrint has the following parameters: Sing