Geek asks and answers

Rock Paper Scissors. Determine win / lose / peg using math?

So, I was writing a game with rock paper scissors when I came to write this function:

a- player in one move, b- player who moves. All I need to find out is to win, lose or tie a player.

//rock=0, paper=1, scissors=2
processMove(a, b) {
    if(a == b) ties++;
    else {
             if(a==0 && b==2) wins++;
        else if(a==0 && b==1) losses++;
        else if(a==1 && b==2) losses++;
        else if(a==1 && b==0) wins++;
        else if(a==2 && b==1) wins++;
        else if(a==2 && b==0) losses++;
    }
}

My question is: what is the most elegant way to write this function?

Edit: I'm looking for one layer.

+5
source share
5 answers
if (a == b) ties++;
else if ((a - b) % 3 == 1) wins++;
else losses++;

I need to know exactly which language you are using in order to turn it into a strictly single-line ...

For JavaScript (or other languages ​​with a weird module) use:

if (a == b) ties++;
else if ((a - b + 3) % 3 == 1) wins++;
else losses++;
+12
source

A 3x3 matrix would be “more elegant," I suppose.

char result = "TWLLTWWLT".charAt(a * 3 + b);

(: , a b .)

+7

I suppose you could use the terniary statement like this:

if (b==0) a==1? wins++ : loss++;

if (b==1) a==1? loss++ : wins++;

if (b==2) a==1? loss++ : wins++;
+2
source

You can do this with a simple mathematical formula to get the result, and then compare with the iffollowing:

var moves = {
  'rock': 0, 
  'paper': 1,
  'scissors': 2
};
var result = {
  'wins': 0,
  'losses': 0,
  'ties': 0
};
var processMove = function (a, b) {
  var processResult = (3 + b - a) % 3;
  if (!processResult) {
    ++result['ties'];
  } else if(1 == processResult) {
    ++result['losses'];
  } else {
    ++result['wins'];
  }
  return result;
};

jsFiddle Demo

One line processMovefunction without return:

var processMove = function (a, b) {
  ((3 + b - a) % 3) ? 1 == ((3 + b - a) % 3) ? ++result.losses : ++result.wins : ++result.ties;
};
+2
source

how do you do it in java?

result = (comp-x)% 3;

System.out.println (result);
 if (result == 0 )// if the game is tie
 {
     System.out.println ("A Tie!") ;
 }

 else if (result == 1 || result == 2 )
 {
    //System.out.println (user + " " +   "beats" + " " + computer_choice + " you win" );
     System.out.println ("comp win");
 }

 else
 {
     System.out.println ("you win");
    //System.out.println (computer_choice  + " " +  "beats" + " " + user + "you lose");
 }
+1
source

More articles: