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  1. Prepare
  2. Java
  3. Data Structures
  4. Java Arraylist
  5. Discussions

Java Arraylist

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802 Discussions

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  • HimaBindhuk
     + 0 comments

    import java.util.ArrayList; import java.util.Scanner;

    public class Solution { public static void main(String[] args) { Scanner scanner = new Scanner(System.in); int n = scanner.nextInt();

        ArrayList<ArrayList<Integer>> lines = new ArrayList<>();
    for (int i = 0; i < n; i++) {
        int d = scanner.nextInt();
        ArrayList<Integer> line = new ArrayList<>();
        for (int j = 0; j < d; j++) {
            line.add(scanner.nextInt());
        }
        lines.add(line);
    }

    int q = scanner.nextInt();
    for (int i = 0; i < q; i++) {
        int x = scanner.nextInt();
        int y = scanner.nextInt();

        try {
            int number = lines.get(x - 1).get(y - 1);
            System.out.println(number);
        } catch (IndexOutOfBoundsException e) {
            System.out.println("ERROR!");
        }
    }
    scanner.close();
}

    }

  • navamsharma142
     + 0 comments

    Is this jagged array question?

  • outsider973
     + 0 comments
    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 row = Integer.parseInt(sc.next());
        sc.nextLine();
        
        List<List<Integer>> input = IntStream.range(0, row)
            .mapToObj(unused -> {
            return Arrays.stream(sc.nextLine().trim().split(" "))
                    .skip(1)
                    .map(Integer::parseInt)
                    .collect(Collectors.toList());
            })
            .collect(Collectors.toList());  
        
        row = sc.nextInt();
        
        IntStream.range(0, row)
        .forEach(unused -> {
            int x = sc.nextInt() - 1;
            int y = sc.nextInt() - 1;
            
            if (x < input.size() && y < input.get(x).size())
                System.out.println(input.get(x).get(y));
            else
                System.out.println("ERROR!");
        });
        
        sc.close();
    }

  • onkarraut317
     + 0 comments

    Hi Team, I have used this approach, let me know any updates

    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();
        List<List<Integer>> mainList = new ArrayList<>();
        for (int i = 0; i < n; i++) {
            int d = sc.nextInt();
            List<Integer> subList = new ArrayList<>();
            for (int j = 0; j < d; j++) {
                subList.add(sc.nextInt());
            }
            mainList.add(subList);
        }
        List<List<Integer>> queryList = new ArrayList<>();
        int q = sc.nextInt();
        for (int k = 0; k < q; k++) {
            List<Integer> query = new ArrayList<>();
            for (int l = 0; l < 2; l++) {
                query.add(sc.nextInt());
            }
            queryList.add(query);
        }

        queryList.forEach(query -> {
            try {
                Integer record = mainList.get(query.get(0) - 1).get(query.get(1) - 1);
                System.out.println(record);
            } catch (Exception e) {
                System.out.println("ERROR!");
            }
        });
       
    }
}

  • jhoneder
     + 0 comments
    import java.util.List;
import java.util.Scanner;
import java.util.stream.Stream;

import static java.util.stream.Collectors.toList;


public class Solution {

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int numberOfArrays = getInputNumber(scanner);
        int numberOfQuerys = 0;
        List<List<Integer>> arraysOfNumbers = new ArrayList<>();
        List<List<Integer>> arrayOfQuery = new ArrayList<>();// x , y in every query

        for (int i = 0; i < numberOfArrays; i++) {
            List<Integer> list = getInputListNumbers(scanner);
            list.remove(0);
            arraysOfNumbers.add(list);
        }

        numberOfQuerys = getInputNumber(scanner);
        while (numberOfQuerys-- > 0) {
            arrayOfQuery.add(getInputListNumbers(scanner));
        }
        scanner.close();

        arrayOfQuery.forEach(list -> {
            int x = list.get(0); // position in array of numbers
            int y = list.get(1);// position in array
            printNumber(x, numberOfArrays, arraysOfNumbers, y);
        });
    }

    private static void printNumber(int x, int numberOfArrays, List<List<Integer>> arraysOfNumbers, int y) {
        if(x <0 || x > numberOfArrays){
            System.out.println("ERROR!");
        }
        List<Integer> array = arraysOfNumbers.get(x -1);
        try{
            System.out.println(array.get(y -1));
        }catch (Exception e){
            System.out.println("ERROR!");
        }
    }

    private static int getInputNumber(Scanner scanner) {
        return Integer.parseInt(scanner.nextLine());
    }

    private static List<Integer> getInputListNumbers(Scanner scanner) {
        return Stream.of(scanner.nextLine().split(" ")).map(Integer::parseInt).collect(toList());
    }
}