Challenge: To-Do List

Lab Java Beginner 10 points

Keep a to-do list in an ArrayList<String>. Read n commands:

add <task> – add the task (one word) at the end
done <task> – remove that task, if it's there

At the end, print the number of tasks left and then each task on its own line, numbered from 1.

Input

First n, then n commands.

Output

Tasks left: <count>
1. <task>
...

Example

Input

4
add shop
add cook
add clean
done cook

Output

Tasks left: 2
1. shop
2. clean

Sample input available Sample output available

Editor

Java

Hints

list.remove("word") removes by value and does nothing if it isn't there.

Use a normal for loop with i so you can print the number i + 1.

Solution explanation

The list grows with add and shrinks with remove, and keeps the order tasks were added.

Show solution

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

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        ArrayList<String> todo = new ArrayList<>();
        for (int i = 0; i < n; i++) {
            String cmd = sc.next();
            String task = sc.next();
            if (cmd.equals("add")) {
                todo.add(task);
            } else {
                todo.remove(task);
            }
        }
        System.out.println("Tasks left: " + todo.size());
        for (int i = 0; i < todo.size(); i++) {
            System.out.println((i + 1) + ". " + todo.get(i));
        }
    }
}

Output

Answer