Rock, Paper, Scissors, Shoot!

See This Post for Live Tournament Info!

LAST RULES UPDATE: See This Post Post for Live Tournament Info!

Motivation

Rock-Paper-Scissors is a popular game all over the world. Let's have a competition where you get to build your own program that plays Rock-Paper-Scissors! If you don't know how the game works, you can read about it here.

The interesting thing about this game is that if you play completely randomly, on average you will do as well as your opponent, regardless of what your opponent does (i.e. you will win 33% of the time, lose 33% of the time, and tie 33% of the time). However, in practice the game is usually not completely random, because human players don't play randomly, and try to psychologically out-smart their opponents. That way it's actually a fun game! But don't worry: we'll use a mechanism to prevent you from making a random bot to spoil the fun! So let's get to the specifics.

The Program

Imagine you are playing rock, paper, scissors with someone, and you want to write a computer program to do your next move for you. You need to write a Python procedure (called player) that takes as input the sequence of your moves and the sequence of your opponents moves represented by a list consisting only of the strings 'rock', 'paper', and 'scissors', and produces as output, your next move (either 'rock', 'paper' or 'scissors'). Your program should only be one function (which can contain other functions), and should not store state (e.g. global variables). Here is an example program that just plays the last move your opponent played:

def player(my_moves, opp_moves):
    if opp_moves != []:
        return opp_moves[-1]
    else:
        return 'rock'

Competition Rules

The First Task

Your program will need to play against three programs I build that aren't very smart. It will play 1000 rounds against each of these bots, and we will let you test this (probably on an IDE quiz on our website before submitting your program). In other words, they will probably have patterns in what moves they do, and they won't try to take your program's moves into account. To get to the next level in the competition, your program will need to beat at least two of these programs with a win rate of at least 50% (if it played randomly, it would be around 33% of the time on average). Your code should take no more than 2 seconds to complete 1000 rounds. This is not a strict limit, but try to stay within that range. You can test your program against our bots here! (Note: This may have some bugs. If certain things aren't working, please tell us!)

The Second Task

If your program passes the first task, it will then enter a tournament with all of the other eligible programs. Each match will have approximately 1000 rounds that you won't see followed by a best 7 out of 13 match (i.e. whoever gets 7 wins first, wins the match). The first set of ~1000 rounds will give your algorithm a chance to learn your opponent's behavior. I haven't decided the logistics of the tournament, because it will depend on the number of submissions.

Your code should be submitted here by Thursday July 26th at 17:00 UTC. You are allowed to submit two programs. (Thank our friend @areke from CS 253 for the awesome submission form!)

There will be a live tournament on Saturday July 28th at 17:00 UTC. The tournament will be hosted on Cloud 9 IDE. I will give you a link to the workspace where you can join us on Saturday before the tournament begins. Check the forums before the tournament to get the link and instructions on what to do! You do not need to sign up for Cloud 9, you just open the link on your browser and enjoy!

Final Remarks

This is very experimental. Let us know what you what you think of this tournament, and if you like this idea, and want similar competitions in the future, let us know by voting this post up. Thanks!

If you want to test two different programs against each other, you can use the following code. Or you can write your own more elegant code.

def match(player1, player2):
    moves1 = []
    moves2 = []
    wins1 = 0
    wins2 = 0
    for i in range(1000):
        move1 = player1(moves1, moves2)
        move2 = player2(moves2, moves1)
        moves1.append(move1)
        moves2.append(move2)
        if winner(move1, move2) == 1:
            wins1 += 1
            # print "Player 1 wins! (%s vs. %s)" %(move1, move2)
        elif winner(move1, move2) == -1:
            wins2 += 1  
            # print "Player 2 wins! (%s vs. %s)" %(move1, move2) 
    print "Player 1 won %d games and Player 2 won %d games" %(wins1, wins2)
    return

def winner(move1, move2):
    dict = {'rock': 0, 'paper': 1, 'scissors': 2}
    a = dict[move1]
    b = dict[move2]
    if a == b:
        return 0
    elif a - b == 1 or a - b == -2:
        return 1
    else:
        return -1