A genetically optimized mahjong table seating randomizer

MahjongMatchmaker.py

#!/usr/bin/env python

import sqlite3 as sql
import random

POPULATION = 256

def main():
    todays_players = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98] # 98
    random.shuffle(todays_players)
    todays_players = todays_players[0:32] # 32 random players
    #todays_players = [40,6,23,26,15,98,1,10,55,16,56,97,96,12,13,41,52,88,66,94,89,86,87,77,79,72,76] # 27 players
    #todays_players = [40,6,23,26,15,98,1,10] # 8 players (best case score 24)
    #todays_players = [97, 96, 12, 13, 41, 52, 88, 66, 94] # 12 players (best case score 14)

    conn = sql.connect('MahjongScores.db')
    playergames = playerGames(todays_players, conn.cursor())
    conn.close()

    tables = bestArrangement(todays_players, playergames)

    print "Final score: " + str(tablesScore(tables, playergames))
    print "Final arrangement: " + str(tables)

def bestArrangement(tables, playergames, population = POPULATION):
    numplayers = len(tables)

    tabless = []
    for i in range(POPULATION):
        random.shuffle(tables)
        tabless += [(tablesScore(tables, playergames), tables)]
    tabless.sort(key=itemgetter(0))

    minScore = tabless[0][0]
    improved = 0

    while improved < numplayers and minScore > 0:
        for j in range(POPULATION):
            newTables = mutateTables(tabless[j][1])
            tabless += [(tablesScore(newTables, playergames), newTables)]
        tabless.sort(key=itemgetter(0))
        tabless = tabless[0:POPULATION]

        improved += 1
        if minScore != tabless[0][0]:
            minScore = tabless[0][0]
            improved = 0

    return tabless[0][1]

def mutateTables(tables):
    tables = tables[:]
    a = random.randint(0, len(tables) - 1)
    b = random.randint(0, len(tables) - 1)
    tables[a], tables[b] = tables[b], tables[a]

    return tables

def tablesScore(players, playergames):
    numplayers = len(players)
    if numplayers >= 8:
        tables_5p = numplayers % 4
        total_tables = int(numplayers / 4)
        tables_4p = total_tables - tables_5p
    else:
        if numplayers >= 5:
            tables_5p = 1
        else:
            tables_5p = 0
        total_tables = 1
        tables_4p = total_tables - tables_5p

    score = 0

    for i in range(0, tables_5p * 5, 5):
        table = players[i:i+5]
        score += tableScore(table, playergames)

    for i in range(tables_5p * 5, numplayers, 4):
        table = players[i:i+4]
        score += tableScore(table, playergames)

    return score

def tableScore(players, playergames):
    numplayers = len(players)

    score = 0
    for i in range(numplayers):
        for j in range(i + 1, numplayers):
            if (players[i], players[j]) in playergames:
                score += playergames[(players[i], players[j])]
            elif (players[j], players[i]) in playergames:
                score += playergames[(players[j], players[i])]
    return score

def playerGames(players, c):
    numplayers = len(players)

    playergames = dict()

    for i in range(numplayers):
        for j in range(i + 1, numplayers):
            games = c.execute("SELECT COUNT(*) FROM Scores WHERE PlayerId = ? AND GameId IN (SELECT GameId FROM Scores WHERE PlayerId = ?)", (players[i], players[j])).fetchone()[0]
            if games != 0:
                playergames[(players[i], players[j])] = games

    return playergames

if __name__ == "__main__":
    main()