Comparison of Tournament Finals Formats

compare_tournament_format.py

A = 0.5
B = 1 - A

import random

def boX(X, a_chance, adv=0):
    """
        Given two teams where team A has an `a_chance` to win and an `adv`
        game advantage, this simulations one best-of-`X` game.
    """
     
    a, b = adv, 0
    to_win = ((X + 1) / 2)
    while a < to_win and b < to_win:
        if random.random() <= a_chance:
            a += 1
        else:
            b += 1

    return a == to_win
    

double_bo3, bo5_adv, bo5_noadv = 0, 0, 0
N = 1000000
A = 0.5
for i in xrange(N):
    if boX(3, A):
        double_bo3 += 1
    elif boX(3, A):
            double_bo3 += 1
    
    if boX(5, A, 1):
        bo5_adv += 1

    if boX(5, A, 0):
        bo5_noadv += 1

print "double bo3: {}".format(100.0 * double_bo3 / N)
print "bo5 with 1 game advantage: {}".format(100.0 * bo5_adv / N)
print "bo5 with no advantage: {}".format(100.0 * bo5_noadv / N)

Sample results:
double bo3: 74.9473
bo5 with 1 game advantage: 68.7583
bo5 with no advantage: 50.0155