hackerank:java-arraylist.java

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

public class Solution {

    

    public static void main(String[] args) {
        /* Enter your code here. Read input from STDIN. Print output to STDOUT. Your class should be named Solution. */
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        ArrayList<ArrayList<Integer>> ip = new ArrayList<ArrayList<Integer>>(n);
    
        for (int i=0; i<n; i++) {
            int d = sc.nextInt();
        
            ArrayList<Integer> innerList = new ArrayList<>();
            
            for(int j=0; j<d ; j++) {
                innerList.add(sc.nextInt());
            }
            
            ip.add(innerList);
        }
    
        int q = sc.nextInt();
        
        for (int i=0; i<q; i++) {
            int x = sc.nextInt();
            int y = sc.nextInt();
            
            try {
                System.out.println(ip.get(x-1).get(y-1)); 
            }catch(Exception err) {
                System.out.println("ERROR!");
            }
        }
        
    }
}