Just write the word! Part 2

"""
solution of:
    https://brilliant.org/problems/just-write-the-word-part-2/?ref_id=1396388
"""
def make_move(cur_pos, dir_code):
    """
    returns the coordinates of a point cur_pos shifted in the given direction
    """
    dir_code_data = {'N': (0, 1), 'S': (0, -1), 'E':(1, 0), 'W':(-1, 0),
                     'NE': (1, 1), 'SE': (1, -1), 'SW': (-1, -1), 'NW': (-1, 1)}
    cur_dir = dir_code_data[dir_code]
    return tuple([cur_pos[_]+cur_dir[_] for _ in range(len(cur_pos))])

def get_rectangular_board(in_word):
    """
    returns a board of the type from the puzzle
    """
    board_data = {}
    for (char_num, cur_char) in enumerate(in_word):
        if char_num == 0:
            board_data[(0, 0)] = cur_char
        else:
            cur_pos = (char_num, char_num)
            for cur_dir in ['S', 'W', 'N', 'E']:
                for _ in range(2*char_num):
                    board_data[cur_pos] = cur_char
                    cur_pos = make_move(cur_pos, cur_dir)
    return board_data

def gen_all_paths(in_board, start_pos, dir_list, target_word):
    """
    generates all paths, which result in a target_word
    """
    def inner(cur_word, cur_path, cur_pos):
        if cur_word == target_word:
            yield cur_path
        elif len(cur_word) < len(target_word) and cur_word == target_word[:len(cur_word)]:
            for cur_dir in dir_list:
                tmp_pos = make_move(cur_pos, cur_dir)
                if tmp_pos in in_board:
                    tmp_word = cur_word+in_board[tmp_pos]
                    tmp_path = cur_path+cur_dir
                    for _ in inner(tmp_word, tmp_path, tmp_pos):
                        yield _
    for _ in inner(in_board[(start_pos)], '', start_pos):
        yield _

TARGET_WORD = 'RADAR'
CUR_BOARD = get_rectangular_board(TARGET_WORD)
ALL_DIR_LIST = ['N', 'S', 'E', 'W', 'NE', 'SE', 'SW', 'NW']
RES = sum((1 for _ in gen_all_paths(CUR_BOARD, (0, 0), ALL_DIR_LIST, TARGET_WORD)))
print(RES)