How to make a random string from array in C#?

Questions & Answers
1

Hi there, guys! I’m making a rubik’s cube game, and there is a timer in it. And it needs to have a random scramble which is in a array (it already has, but it’s not a good one). Look:

public Button botao;
public Sprite imagemStart;
public List<string> Scramble;
public Text textScramble; 
public float mil;
public float sec;
public int min;

public void ChangeBool(){
		BtnBoolean = !BtnBoolean;
		sec = 0;
		mil = 0;
		min = 0;
		 textScramble.text =	"";
     	if(!BtnBoolean){
     		int i = 0;
     		while(i < 12){      			
         textScramble.text += Scramble[UnityEngine.Random.Range(0, Scramble.Count - 1)].ToString(); 
         	i ++;
         }
          botao.image.overrideSprite = imagemStart;    
     	}     		   
	}

It works, but it has some issues like this:

82138-issue.png
82138-issue.png1136×768 99 KB

It must not repeat the previous algorithm.
So, my question is: How can I make a random algorithm (R or R’ or R2 or L or L’ or L2, etc) wihtout repeating the previous movement (letter)?
Sorry for my bad english. Please, can someone help me?

2

I thought in some like:

 while(i < 12){
       if(Scramble != previousLetter || Scramble != previousPreviousLetter){       
       textScramble.text += Scramble[UnityEngine.Random.Range(0, Scramble.Count - 1)].ToString(); 
              i ++;
            }
          }