usrbinenv python3 the bifid cipher uses a polybius square to encipher a message in a way that makes it fairly difficult to decipher without knowing the secret https www braingle combrainteaserscodesbifid php return the pair of numbers that represents the given letter in the polybius square np arrayequalbifidcipher lettertonumbers a 1 1 true np arrayequalbifidcipher lettertonumbers u 4 5 true return the letter corresponding to the position index1 index2 in the polybius square bifidcipher numberstoletter4 5 u true bifidcipher numberstoletter1 1 a true return the encoded version of message according to the polybius cipher bifidcipher encode testmessage qtltbdxrxlk true bifidcipher encode test message qtltbdxrxlk true bifidcipher encode test j bifidcipher encode test i true return the decoded version of message according to the polybius cipher bifidcipher decode qtltbdxrxlk testmessage true usr bin env python3 the bifid cipher uses a polybius square to encipher a message in a way that makes it fairly difficult to decipher without knowing the secret https www braingle com brainteasers codes bifid php return the pair of numbers that represents the given letter in the polybius square np array_equal bifidcipher letter_to_numbers a 1 1 true np array_equal bifidcipher letter_to_numbers u 4 5 true return the letter corresponding to the position index1 index2 in the polybius square bifidcipher numbers_to_letter 4 5 u true bifidcipher numbers_to_letter 1 1 a true return the encoded version of message according to the polybius cipher bifidcipher encode testmessage qtltbdxrxlk true bifidcipher encode test message qtltbdxrxlk true bifidcipher encode test j bifidcipher encode test i true return the decoded version of message according to the polybius cipher bifidcipher decode qtltbdxrxlk testmessage true
import numpy as np

SQUARE = [
    ["a", "b", "c", "d", "e"],
    ["f", "g", "h", "i", "k"],
    ["l", "m", "n", "o", "p"],
    ["q", "r", "s", "t", "u"],
    ["v", "w", "x", "y", "z"],
]


class BifidCipher:
    def __init__(self) -> None:
        self.SQUARE = np.array(SQUARE)

    def letter_to_numbers(self, letter: str) -> np.ndarray:
        
        index1, index2 = np.where(letter == self.SQUARE)
        indexes = np.concatenate([index1 + 1, index2 + 1])
        return indexes

    def numbers_to_letter(self, index1: int, index2: int) -> str:
        
        letter = self.SQUARE[index1 - 1, index2 - 1]
        return letter

    def encode(self, message: str) -> str:
        
        message = message.lower()
        message = message.replace(" ", "")
        message = message.replace("j", "i")

        first_step = np.empty((2, len(message)))
        for letter_index in range(len(message)):
            numbers = self.letter_to_numbers(message[letter_index])

            first_step[0, letter_index] = numbers[0]
            first_step[1, letter_index] = numbers[1]

        second_step = first_step.reshape(2 * len(message))
        encoded_message = ""
        for numbers_index in range(len(message)):
            index1 = int(second_step[numbers_index * 2])
            index2 = int(second_step[(numbers_index * 2) + 1])
            letter = self.numbers_to_letter(index1, index2)
            encoded_message = encoded_message + letter

        return encoded_message

    def decode(self, message: str) -> str:
        
        message = message.lower()
        message.replace(" ", "")
        first_step = np.empty(2 * len(message))
        for letter_index in range(len(message)):
            numbers = self.letter_to_numbers(message[letter_index])
            first_step[letter_index * 2] = numbers[0]
            first_step[letter_index * 2 + 1] = numbers[1]

        second_step = first_step.reshape((2, len(message)))
        decoded_message = ""
        for numbers_index in range(len(message)):
            index1 = int(second_step[0, numbers_index])
            index2 = int(second_step[1, numbers_index])
            letter = self.numbers_to_letter(index1, index2)
            decoded_message = decoded_message + letter

        return decoded_message