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:

1std::vector<std::string> 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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#include "gtest/gtest.h"

#include <iostream>

​

#include <vector>

​

std::string getFinalStr(std::string str);

​

bool isDollarDeleteEqual(std::vector<std::string> arr) {

    // fill in

    // with solution

    return false;

}

​

std::string getFinalStr(std::string str) {

    // fill in

    // with solution

    return "";

}

​

// print your findings using this function!

#define LOG

void log() {

    std::cout << isDollarDeleteEqual({ "f$st", "st" });

}

​

​

​

​

int main(int argc, char** argv) {

Here's how we would solve this problem...

How do I use this guide?