HackerRank Solution: Java Arraylist

import java.io.*;

import java.util.*;

import java.util.Collection.*;

public class Solution {

public static void main(String[] args) {

Scanner sc = new Scanner(System.in);

int n = sc.nextInt();

ArrayList<ArrayList<Integer>> all = new ArrayList<>();

for(int i=0;i<n;i++)

{

int d = sc.nextInt();

ArrayList<Integer> l = new ArrayList<>();

for(int j=0;j<d;j++)

{

l.add(sc.nextInt());

}

all.add(l);

}

int q = sc.nextInt();

for(int i=0;i<q;i++)

{

int q1 = sc.nextInt();

int q2 = sc.nextInt();

if(q2 > all.get(q1–1).size())

System.out.println(“ERROR!”);

else

System.out.println(all.get(q1–1).get(q2 -1));

}

}

}