find_connect_four_winner.py

import re


def get_new_board():
    # board[row][column]
    return [["" for _ in range(7)] for _ in range(6)]


t = {
    "Red": "R",
    "Yellow": "Y",
    "": "-",
}


def print_board(board):
    print("")
    for row in board:
        print(" ".join([t[v] for v in row]))


def print_board_with_checks_highlighted(board, check_locations):
    print("")
    for y, row in enumerate(board):
        print(" ".join([f"\033[94m{t[v]}\033[0m" if (y, x) in check_locations else t[v] for x, v in enumerate(row)]))


def find_lowest_available_row_for_col(board, board_col):
    for i, row in enumerate(board):
        if row[board_col]:
            return i - 1
    return len(board) - 1


def four_values_are_equal(values):
    return values[0] and all(v == values[0] for v in values)


def check_rows(board):
    for row in board:
        for x in range(0, len(row) - 3):
            values = [row[y] for y in range(x, x + 4)]
            if four_values_are_equal(values):
                return values[0]


def check_cols(board):
    rotated_board = list(zip(*board[::-1]))
    return check_rows(rotated_board)


def check_diagonals(board):
    # down to right
    for y in range(0, len(board) - 3):
        for x in range(0, len(board[y]) - 3):
            # check_locations = [(y + z, x + z) for z in range(4)]
            # print_board_with_checks_highlighted(board, check_locations)
            values = [board[y + z][x + z] for z in range(4)]
            if four_values_are_equal(values):
                return values[0]
    # down to left
    for y in range(len(board) - 4, -1, -1):
        for x in range(len(board[y]) - 1, len(board[y]) - 5, -1):
            # check_locations = [(y + z, x - z) for z in range(4)]
            # print_board_with_checks_highlighted(board, check_locations)
            values = [board[y + z][x - z] for z in range(4)]
            if four_values_are_equal(values):
                return values[0]


def who_is_winner(pieces_position_list):
    board = get_new_board()

    checks = [check_rows, check_cols, check_diagonals]

    for move_count, move in enumerate(pieces_position_list):
        [(col_letter, player)] = re.findall("(.)_(.*)", move)
        col = ord(col_letter.lower()) - 97
        row = find_lowest_available_row_for_col(board, col)
        board[row][col] = player
        if move_count < 7:
            continue
        for check in checks:
            winner = check(board)
            if winner:
                return winner
    return "Draw"


game_winner = who_is_winner([
    "C_Yellow", "E_Red", "G_Yellow", "B_Red", "D_Yellow", "B_Red", "B_Yellow", "G_Red", "C_Yellow", "C_Red",
    "D_Yellow", "F_Red", "E_Yellow", "A_Red", "A_Yellow", "G_Red", "A_Yellow", "F_Red", "F_Yellow", "D_Red",
    "B_Yellow", "E_Red", "D_Yellow", "A_Red", "G_Yellow", "D_Red", "D_Yellow", "C_Red"
])

print(game_winner)