How to make the passage of the level using the desired key sequence?

Question

Unity

To pass the level, you need to press two keys in a certain sequence. For example, the player is given the following text, +-++-+---+--+-. In this case, plus is the A key, respectively, minus is D. To pass the level, you need to press the keys in the correct order, but if the player presses an unnecessary key, the whole order is reset. What is the easiest way to do this?

Answer 1

Write to the buffer the keys pressed by the player.
For example, at least in list.
When you press the wrong key, you simply reset the list.

Answer 2

More or less like this. The code didn't run.

int counter = 0;
string target = "adadadddaaa";

void Update()
{
        string input = Input.inputString;

        if (!string.IsNullOrEmpty(input))
        {
            if (input.ToCharArray()[0] == target[counter])
            {
                counter++;
                if (counter >= target.Length)
                { // next level
                }
            }
            else
            {
                // wrong char! restart
            }
        }
}