``from collections import Counterdef equal_number_of_letters_and_numbers(string: str):    """    Given an array filled with letters and numbers, fnd the longest subarray with    an equal number of letters and numbers    :param string: string    :return: subarray    """    number_count = []    letter_count = []    # count the number of letters and numbers    for i in string:        if i.isdigit():            number_count.append(1 if len(number_count) == 0 else number_count[-1] + 1)            letter_count.append(0 if len(letter_count) == 0 else letter_count[-1])        else:            letter_count.append(1 if len(letter_count) == 0 else letter_count[-1] + 1)            number_count.append(0 if len(number_count) == 0 else number_count[-1])    diff = []    # Calculate the difference in each position    for i in range(0, len(number_count)):        diff.append(letter_count[i] - number_count[i])    print(' '.join(map(lambda x: str(x).center(3), list(range(0, len(diff))))))    print(' '.join(map(lambda x: str(x).center(3), list(string))))    print(' '.join(map(lambda x: str(x).center(3), letter_count)))    print(' '.join(map(lambda x: str(x).center(3), number_count)))    print(' '.join(map(lambda x: str(x).center(3), diff)))    # the result is the furthest value of same difference    counter = Counter(diff)    largest_diff_range = (None, None)    largest_index = (None, None)    for (value, counts) in counter.most_common():        if counts <= 1:            continue        first_index = diff.index(value)        last_index = len(diff) - 1 - list(reversed(diff)).index(value)        difference = last_index - first_index        if largest_diff_range[0] is None or difference > largest_diff_range[0]:            largest_diff_range = (difference, value)            largest_index = (first_index, last_index)    # first substring starts from +1 of the range    result = string[largest_index[0] + 1: largest_index[1] + 1]    print(result)    return resultif __name__ == "__main__":    equal_number_of_letters_and_numbers("aaaa11a11aa1aa1aaaaa")``