Good morning! Here's our prompt for today.

You're given an array of strings containing alphabetical characters and certain $ characters. A $ represents a DELETE action whereby the character before it is deleted.

Each of these strings will be run through a method to operate on the $ DELETE action. We want to find out if the final string is the same for all of them. Let's take an example:

1string[] input = {"f$st", "st"};
2IsDollarDeleteEqual(input);
3// true
4// true because both become "st"

Can you find a solution in O(n) time and constant space?

Constraints

• The input arrays can be of any size
• Every string has at least a single character
• The string will consist of dollar signs and lowercase alphabets
• Expected overall time complexity : O(n)
• Expected space complexity : O(n) for good solution, O(1) for asymptotically optimal solution

Try to solve this here or in Interactive Mode.

How do I practice this challenge?

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​

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Text.RegularExpressions;

using NUnit.Framework;

​

using System;

​

class Program

{

  public static bool IsDollarDeleteEqual(string[] arr)

  {

    // fill in

    // with solution

    return false;

  }

​

  private static string GetFinalStr(string str)

  {

    // fill in

    // with solution

    return "";

  }

}

​

​

​

// tests

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