tournament_1.py

#! /usr/bin/env python

import sys
import random

def generate(a, b):
    n = len(a); n_round = 0;
    while n > 1:
        assert(len(a) == len(b)) # safety check
        print "Round => " + str(n_round + 1)
        if n % 2 == 0:
            # construct teams
            teams = list(); i = 0;
            while i < n:
                teams.append((a[i], b[i + 1]))
                teams.append((a[i + 1], b[i]))
                i = i + 2
            print "Teams => " + str(teams)
            # play teams against one another and get the winners
            winners = list(); i = 0;
            while i < n:
                winners.append(random.choice([teams[i], teams[i + 1]]))
                i = i + 2
            print "Winners => " + str(winners)
            # update the list of players
            a, b = list(), list()
            for w in winners:
                a.append(w[0])
                b.append(w[1])
        else:
            # hold one (random) pair out (so that they're not paired together either)
            index = random.choice(xrange(0, n))
            a_index, b_index = a[index], b[index]
            a = a[0:index] + a[index + 1:]
            b = b[0:index] + b[index + 1:]
            n = len(a)
            # construct teams
            teams = list(); i = 0;
            while i < n:
                teams.append((a[i], b[i + 1]))
                teams.append((a[i + 1], b[i]))
                i = i + 2
            print "Teams => " + str(teams)
            print "(Held out " + str((a_index, b_index)) + ")"
            # play teams against one another and get the winners
            winners = list(); i = 0;
            while i < n:
                winners.append(random.choice([teams[i], teams[i + 1]]))
                i = i + 2
            print "Winners => " + str(winners)
            # update the list of players
            a, b = list(), list()
            for w in winners:
                a.append(w[0])
                b.append(w[1])
            # add the team which was held out
            a.append(a_index)
            b.append(b_index)
        print "\n"
        n = len(a); n_round = n_round + 1
    print "Final winner => " + str((a[0], b[0])) + "\n"

if __name__ == "__main__":
    try:
        num_players = int(sys.argv[1])
    except:
        print "Usage: python %s <num_players>" % sys.argv[0]
        sys.exit(1)
    else:
        a = map(lambda x: 'a' + str(x), xrange(1, num_players + 1))
        b = map(lambda x: 'b' + str(x), xrange(1, num_players + 1))
        generate(a, b)