tournament.py

"""
https://cs50.harvard.edu/x/2023/labs/6/
"""

import csv
import sys
import random

# Number of simluations to run.
N = 100


def main():

    # Ensure correct usage.
    if len(sys.argv) != 2:
        sys.exit("Usage: python tournament.py FILENAME")

    # Read teams into memory.
    teams = []

    with open(sys.argv[1]) as file:
        reader = csv.DictReader(file)

        for team in reader:
            team["rating"] = int(team["rating"])
            teams.append(team)

    # Keep track of number of wins for each team.
    counts = {}

    for _ in range(N):
        winner = simulate_tournament(teams)

        if winner in counts:
            counts[winner] += 1
        else:
            counts[winner] = 1

    # Print each team's chances of winning, according to simulation.
    for team in sorted(counts, key=lambda team: counts[team], reverse=True):
        print(f"{team}: {counts[team] * 100 / N:.1f}% chance of winning")


def simulate_game(team1, team2):
    """Simulate a game. Return True if team1 wins, False otherwise."""

    rating1 = team1["rating"]
    rating2 = team2["rating"]
    probability = 1 / (1 + 10 ** ((rating2 - rating1) / 600))

    return random.random() < probability


def simulate_round(teams):
    """Simulate a round. Return a list of winning teams."""

    winners = []

    # Simulate games for all pairs of teams.
    for i in range(0, len(teams), 2):
        if simulate_game(teams[i], teams[i + 1]):
            winners.append(teams[i])
        else:
            winners.append(teams[i + 1])

    return winners


def simulate_tournament(teams):
    """Simulate a tournament. Return name of winning team."""

    while len(teams) != 1:
        teams = simulate_round(teams)

    return teams[0]["team"]


if __name__ == "__main__":
    main()