# Java ArrayList | HackerRank Solution

Hello coders, today we are going to solve Java ArrayList HackerRank Solution.

## Problem

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 105.

## Output Format

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

#### Sample Input

`````` 5
5 41 77 74 22 44
1 12
4 37 34 36 52
0
3 20 22 33
5
1 3
3 4
3 1
4 3
5 5``````

#### Sample Input

`````` 74
52
37
ERROR!
ERROR!``````

#### Explanation

The diagram below explains the queries:

## Solution –Java ArrayList

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

public class Solution {

public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
int n = sc.nextInt();
String s = sc.nextLine();
ArrayList<ArrayList<String>> a = new ArrayList<ArrayList<String>>(n);
for (int i = 0; i < n; i++) {
s = sc.nextLine();
}

int m = sc.nextInt();
for (int i = 0; i < m; i++) {
int x = sc.nextInt();
int y = sc.nextInt();
if (x <= a.size() && y < a.get(x-1).size() && y >= 0) {
System.out.println(a.get(x-1).get(y));
} else {
System.out.println("ERROR!");
}
}
}
}```

Disclaimer: The above Problem ( Java ArrayList ) is generated by Hacker Rank but the Solution is Provided by CodingBroz. This tutorial is only for Educational and Learning Purpose.